Use of pre t alpha or functional variant thereof for expanding tcr alpha deficient t cells

ABSTRACT

A method of expanding TCRalpha deficient T-cells by expressing pTalpha or functional variants thereof into said cells, thereby restoring a functional CD3 complex. This method is particularly useful to enhance the efficiency of immunotherapy using primary T-cells from donors. This method involves the use of pTalpha or functional variants thereof and polynucleotides encoding such polypeptides to expand TCRalpha deficient T-cells. Such engineered cells can be obtained by using specific rare-cutting endonuclease, preferably TALE-nucleases. The use of Chimeric Antigen Receptor (CAR), especially multi-chain CAR, in such engineered cells to target malignant or infected cells. The invention opens the way to standard and affordable adoptive immunotherapy strategies for treating cancer and viral infections.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. 119(e) to U.S.Provisional Application No. 61/651,933, filed May 25, 2012; and to U.S.Provisional Application No. 61/696,612, filed Sep. 4, 2012, which arehereby incorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention concerns cell therapy and more specificallyrelates to a method of expanding TCRalpha deficient T-cells byexpressing preTCRα (“pTalpha”) or functional variants thereof into saidcells, thereby restoring a functional CD3 complex. This method isparticularly useful to enhance the efficiency of immunotherapy usingprimary T-cells from donors. This method involves the use of pTalpha orfunctional variants thereof and polynucleotides encoding suchpolypeptides to expand TCRalpha deficient T-cells. Such engineered cellscan be obtained by using specific rare-cutting endonuclease, preferablyTALE-nucleases. The invention further relates to the use of ChimericAntigen Receptor (CAR), especially multi-chain CAR, in such engineeredcells to target malignant or infected cells. The invention opens the wayto standard and affordable adoptive immunotherapy strategies fortreating cancer and viral infections.

BACKGROUND OF THE INVENTION

Adoptive immunotherapy, which involves the transfer of autologousantigen-specific T cells generated ex vivo, is a promising strategy totreat viral infections and cancer. The T cells used for adoptiveimmunotherapy can be generated either by expansion of antigen-specific Tcells or redirection of T cells through genetic engineering (Park,Rosenberg et al. 2011). Transfer of viral antigen specific T cells is awell-established procedure used for the treatment of transplantassociated viral infections and rare viral-related malignancies.Similarly, isolation and transfer of tumor specific T cells has beenshown to be successful in treating melanoma.

Novel specificities in T cells have been successfully generated throughthe genetic transfer of transgenic T cell receptors or chimeric antigenreceptors (CARs) (Jena, Dotti et al. 2010). CARs are synthetic receptorsconsisting of a targeting moiety that is associated with one or moresignaling domains in a single fusion molecule. In general, the bindingmoiety of a CAR consists of an antigen-binding domain of a single-chainantibody (scFv), comprising the light and variable fragments of amonoclonal antibody joined by a flexible linker. Binding moieties basedon receptor or ligand domains have also been used successfully. Thesignaling domains for first generation CARs are derived from thecytoplasmic region of the CD3zeta or the Fc receptor gamma chains. Firstgeneration CARs have been shown to successfully redirect T cellcytotoxicity, however, they failed to provide prolonged expansion andanti-tumor activity in vivo. Signaling domains from co-stimulatorymolecules including CD28, OX-40 (CD134), and 4-1BB (CD137) have beenadded alone (second generation) or in combination (third generation) toenhance survival and increase proliferation of CAR modified T cells.CARs have successfully allowed T cells to be redirected against antigensexpressed at the surface of tumor cells from various malignanciesincluding lymphomas and solid tumors (Jena, Dotti et al. 2010).

Present CAR architectures are built on a design in which all relevantdomains are contained within a single polypeptide. This designnecessitates serial appending of signaling domains, thus necessitatingmoving some domains from their natural juxtamembrane positions. Thus,architectures in which ligands and signaling domains are separate mayallow for improved function of costimulatory domains placed on differentchains in their normal juxtamembrane positions, rather than appendedtogether with some domains positioned distal from the plasma membrane. Anatural receptor, the high affinity receptor for IgE (FcεRI) wouldafford such architecture. FcεRI present on mast cells and basophilsbinds IgE with high affinity. FcεRI is a tetrameric receptor complexconsisting of ligand binding alpha subunit, a beta subunit and ahomodimer of two signal-transducing gamma subunits (Metzger, Alcaraz etal. 1986). FcεRI alpha domain consists of an extracellular domaincontaining two Ig-like domains that bind IgE, a transmembrane domain anda short cytoplasmic tail. Beta subunit contains four transmembranesegments separating amino and carboxy terminal cytoplasmic tails. Thegamma chain consists essentially of a transmembrane region andcytoplasmic tail containing one immunoreceptor tyrosine-based activationmotif (ITAM) (Cambier 1995). The zeta chain of the TCR complex isclosely related to the gamma chain and can substitute for the gammachain of FcεRI (Howard, Rodewald et al. 1990).

The current protocol for treatment of patients using adoptiveimmunotherapy is based on autologous cell transfer. In this approach, Tlymphocytes are recovered from patients, genetically modified orselected ex vivo, cultivated in vitro in order to amplify the number ofcells if necessary and finally infused into the patient. In addition tolymphocyte infusion, the host may be manipulated in other ways thatsupport the engraftment of the T cells or their participation in animmune response, for example pre-conditioning (with radiation orchemotherapy) and administration of lymphocyte growth factors (such asIL-2). Each patient receives an individually fabricated treatment, usingthe patient's own lymphocytes (i.e. an autologous therapy). Autologoustherapies face substantial technical and logistic hurdles to practicalapplication, their generation requires expensive dedicated facilitiesand expert personnel, they must be generated in a short time following apatient's diagnosis, and in many cases, pretreatment of the patient hasresulted in degraded immune function, such that the patient'slymphocytes may be poorly functional and present in very low numbers.Because of these hurdles, each patient's autologous cell preparation iseffectively a new product, resulting in substantial variations inefficacy and safety. Ideally, one would like to use a standardizedtherapy in which allogeneic therapeutic cells could be pre-manufactured,characterized in detail, and available for immediate administration topatients. By allogeneic it is meant that the cells are obtained fromindividuals belonging to the same species but are geneticallydissimilar. However, the use of allogeneic cells presently has manydrawbacks. In immune-competent hosts allogeneic cells are rapidlyrejected, a process termed host versus graft rejection (HvG), and thissubstantially limits the efficacy of the transferred cells. Inimmune-incompetent hosts, allogeneic cells are able to engraft, buttheir endogenous TCR specificities recognize the host tissue as foreign,resulting in graft versus host disease (GvHD), which can lead to serioustissue damage and death. In order to effectively use allogeneic cells,both of these problems must be overcome.

In immunocompetent hosts, allogeneic cells are rapidly rejected by thehost immune system. It has been demonstrated that, allogeneic leukocytespresent in non-irradiated blood products will persist for no more than 5to 6 days. (Boni, Muranski et al. 2008). Thus, to prevent rejection ofallogeneic cells, the host's immune system must be effectivelysuppressed. Glucocorticoidsteroids are widely used therapeutically forimmunosuppression (Coutinho and Chapman 2011). This class of steroidhormones binds to the glucocorticoid receptor (GR) present in thecytosol of T cells resulting in the translocation into the nucleus andthe binding of specific DNA motifs that regulate the expression of anumber of genes involved in the immunologic process. Treatment of Tcells with glucocorticoid steroids results in reduced levels of cytokineproduction leading to T cell anergy and interfering in T cellactivation. Alemtuzumab, also known as CAMPATH1-H, is a humanizedmonoclonal antibody targeting CD52, a 12 amino acidglycosylphosphatidyl-inositol-(GPI) linked glycoprotein (Waldmann andHale 2005). CD52 is expressed at high levels on T and B lymphocytes andlower levels on monocytes while being absent on granulocytes and bonemarrow precursors. Treatment with Alemtuzumab, a humanized monoclonalantibody directed against CD52, has been shown to induce a rapiddepletion of circulating lymphocytes and monocytes. It is frequentlyused in the treatment of T cell lymphomas and in certain cases as partof a conditioning regimen for transplantation. However, in the case ofadoptive immunotherapy the use of immunosuppressive drugs will also havea detrimental effect on the introduced therapeutic T cells. Therefore,to effectively use an adoptive immunotherapy approach in theseconditions, the introduced cells would need to be resistant to theimmunosuppressive treatment.

On the other hand, T cell receptors (TCR) are cell surface receptorsthat participate in the activation of T cells in response to thepresentation of antigen. The TCR is generally made from two chains,alpha and beta, which assemble to form a heterodimer and associates withthe CD3-transducing subunits to form the T-cell receptor complex presenton the cell surface. Each alpha and beta chain of the TCR consists of animmunoglobulin-like N-terminal variable (V) and constant (C) region, ahydrophobic transmembrane domain, and a short cytoplasmic region. As forimmunoglobulin molecules, the variable region of the alpha and betachains are generated by V(D)J recombination, creating a large diversityof antigen specificities within the population of T cells. However, incontrast to immunoglobulins that recognize intact antigen, T cells areactivated by processed peptide fragments in association with an MHCmolecule, introducing an extra dimension to antigen recognition by Tcells, known as MHC restriction. Recognition of MHC disparities betweenthe donor and recipient through the T cell receptor leads to T cellproliferation and the potential development of GVHD. It has been shownthat normal surface expression of the TCR depends on the coordinatedsynthesis and assembly of all seven components of the complex (Ashwelland Klusner 1990). The inactivation of TCRalpha or TCRbeta can result inthe elimination of the TCR from the surface of T cells preventingrecognition of alloantigen and thus GVHD. However, TCR disruptionresults in the elimination of the CD3 signaling component and alters themeans of further T cell expansion.

In normal T-cells, T cell receptors emanate from the pre-T cellreceptors (pTCR) which are expressed by immature thymocytes and arecrucial for T cell development from the double negative (CD4− CD8−) tothe double-positive (CD4+ CD8+) stages. Pre-T cells that succeed inproductive rearrangements of the TCRbeta locus express a functionalTCRbeta chain which pairs with an invariant preTalpha chain and CD3signaling components to form the pre-TCR complex. The expression of thepreTCR at the cell surface is necessary for triggering beta-selection, aprocess that induces the expansion of developing T cells, enforcesallelic exclusion of the TCRbeta locus and results in the induction ofrearrangements at the TCRalpha locus (von Boehmer 2005). Afterproductive TCRalpha rearrangements and substitution of pTalpha byTCRalpha to form a mature TCR, thymocytes undergo a second step ofselection, referred to as positive or TCRalpha/beta selection uponbinding of self peptide MHC complexes expressed on thymic epithelialcells. Thus, mature T cells recognize and respond to the antigen/MHCcomplex through their TCR. The most immediate consequence of TCRactivation is the initiation of signaling pathways via the associatedCD3 subunits that result in multiple events including clonal expansionof T cells, upregulation of activation markers on the cell surface andinduction of cytotoxicity or cytokine secretion.

Because of the nature of selection of TCRbeta chains through pairingwith preTalpha during thymic development, in T cells in which TCRalphahas been inactivated, the heterologous introduction of the pTalphatransgene can result in the formation of a preTCR. This pTCR can serveas a means of T cell activation or stimulation in a manner that isnon-MHC dependent, thus for example allowing continued expansion ofalpha/beta T-cells following TCRalpha inactivation. Importantly, thepTCR complex displays a similar biochemical composition as the TCR interms of associated CD3 subunits (Carrasco, Ramiro et al. 2001). Inaddition, in contrast to the TCR, pre-TCR signaling may occur in part bya ligand independent event. The crystal structure of the pTCRextracellular domain has provided a structural basis for the possibleligand-independence of pTCR signaling. The pTCR has been shown to form ahead to tail dimer where two pTalpha-TCRbeta heterodimers associate(Pang, Berry et al. 2010).

In the present invention, the inventors have achieved the production ofgenetically modified T-cells, which overcome the limitations of presentimmunotherapy strategies, allowing them to be both non-alloreactive andresistant to immunosuppressive agents. This was made possible by geneinactivation using specific TALE-nucleases directed against TCRalpha orTCRbeta, coupled with inactivation of genes encoding targets fordifferent immunosuppressive agents, in particular CD52 and GR.

In particular, the inactivation of TCRalpha or TCRbeta coupled withinactivation of CD52 or the glucocorticoid receptor in T lymphocytesderived from an allogeneic donor significantly reduces the risk of GVHD,by eliminating the TCR, responsible for recognition of MHC disparities,while permitting proliferation and activity of the introducedlymphocytes in the presence of immunosuppressive drugs, such asAlemtuzumab or glucocorticoid steroids, that prevent rejection of thesecells. Thus, these modified allogeneic T cells are expected to moreefficiently expand in patient's blood, where they can target tumor cellsor infected cells.

In addition to the above conception of genetically modified T cells,which can be both non alloreactive and immunosuppressive resistant, theinventors, by the use and design of specific TALE-nucleases, haveconcomitantly inactivated these different genes in T-cells, therebyobtaining double mutants. As a matter of fact, double gene targeting byDSB has been so far unachieved in T cells due to the difficulty ofyielding and maintaining T-cells in culture over time, to their lowtransformation rates, and loss during selection procedures. Thesedifficulties result in a low probability of success for obtaining suchcells.

Thus, one significant part of the invention is to have designed specificTALE-nucleases, allowing higher rates of DSB events within the T-cells,which are well tolerated by the cells, (especially uponco-transfection), able to target the selection of genes according to theinvention. By using rare cutting endonucleases, such as theTALE-nucleases described therein, the probability of obtaining doubleinactivation of the genes in the transfected T-cells was significantlyincreased, so that it now appears possible to produce engineered T cellsavailable from donors on a regular basis, using standard procedures.

In addition, the present invention proposes an embodiment where T-cellsare engineered to allow proliferation when TCRalpha is inactivated. Asignificant problem with T-cells that have undergone TCR subunitinactivation is that the cells can no longer be expanded through the CD3complex. To overcome this problem, the inventors indeed provide means toexpand T-cells in which TCRalpha has been inactivated through the CD3complex, by expression of preTalpha in the cells, thus restoring afunctional CD3 complex in the absence of a functional alpha/beta TCR.

Finally, T cells are further transformed with CAR to redirect allogeneiccells specificity towards tumor associated antigens independent of MHC.In particular, the invention relates to a multi-chain CAR, in whichcostimulatory domains are placed in their normal juxtamembrane positionsto improve their functions and so enhance survival and increaseproliferation of engineered T-cells. As a result, the invention providesmethods, polypeptides and polynucleotides that allow the effectivetransformation of allogeneic T cells for adoptive immunotherapy, andtheir facile expansion through the CD3 complex.

SUMMARY OF THE INVENTION

In one aspect, the present invention discloses methods to engineer Tcells, in particular allogeneic T cells obtainable from donors, to makethem suitable for immunotherapy purposes. The methods of the presentinvention more particularly allow the precise modification of the genomeof cells relevant for immunotherapy by inactivating or replacing genesinvolved in MHC recognition and or targets of immunosuppressive drugsfor the treatment of cancer and/or viral infections. In certainembodiments, the modified cells relevant for immunotherapy furthercomprise exogenous recombinant polynucleotides encoding CARs forspecific cell recognition. Present CARs are single fusion molecules thatnecessitate serial appending of signaling domains. Moving signalingdomains from their natural juxtamembrane position may interfere withtheir function. Thus, to overcome this drawback, the inventors design amulti-chain CAR derived from FcεRI to allow normal juxtamembraneposition of all relevant signaling domains. The high affinity IgEbinding domain of FcεRI alpha chain is replaced by an extracellularligand-binding domain such as scFv to redirect T-cell specificity tocell targets and the N and/or C-termini tails of FcεRI beta chain isused to place costimulatory signals in normal juxtamembrane positions.

In another aspect, in order to promote activation or stimulation of Tcells in which TCRalpha has been inactivated, pTalpha or functionalvariant thereof are introduced into the engineered T-cells. The pTalphaor functional variant thereof used can be either full-length pTalpha, asplice variant (Saint-Ruf, Lechner et al. 1998), a C-terminal truncatedversion that has been shown to increase preTCR cell surface expression(Carrasco, Ramiro et al. 2001). Other additional truncations eithersmaller or larger than that described could be used. Different preTalphaversions may further comprise signaling moieties from other molecules(CD28, CD137, CD8, TCRalpha, etc.) to promote proliferation and survivalor comprise mutations that affect its ability to dimerize, such as theD22A, R24A, R102A or R117A mutations previously described in mice(Yamasaki, Ishikawa et al. 2006) or the W46R mutation described inhumans (Pang, Berry et al. 2010) to decrease the proliferationpotential. The scFv portion of the CAR may also be fused to theextracellular domain of a pTalpha or a functional variant thereof, thuscoupling the specificity towards target antigens directly with theproliferative activity of the preTCR.

In another aspect, the present invention relates to the polypeptides andthe polynucleotides, which encode the rare-cutting endonucleases, toprecisely target the above genes of interest, in particular TCRalpha,TCRbeta, GR and CD52, thereby enabling the genetic modification of theT-cells for immunotherapy. The present invention provides moreparticularly specific target sequences within these genes andTALE-nucleases designed to respectively target those genes.

The present invention also relates to the isolated cells or cell linescomprising any of the proteins, polypeptides or vectors describedherein. In certain embodiments, the T cells of the present inventioncomprise inactivated TCRalpha, TCRbeta, GR or CD52 genes for their usein immunotherapy. The isolated cells of the present invention or celllines can further comprise exogenous recombinant polynucleotides, inparticular polynucleotides encoding pTalpha or functional variantthereof, CARs or multi-chain CARs.

In a preferred embodiment, the modified T cells are used as atherapeutic product, ideally as an “off the shelf” product.

In another aspect, the present invention concerns the method fortreating or preventing cancer or infections in the patient byadministrating an engineered T-cell obtainable by the above methods.

BRIEF DESCRIPTION OF THE FIGURES AND TABLES

In addition to the preceding features, the invention further comprisesother features which will emerge from the description which follows, aswell as to the appended drawings. A more complete appreciation of theinvention and many of the attendant advantages thereof will be readilyobtained as the same becomes better understood by reference to thefollowing Figures in conjunction with the detailed description below.

FIG. 1: Schematic representation of the normal relationship betweenT-cells and antigen presenting cell.

FIG. 2: Schematic representation of the genetically modified therapeuticT-cells according to the invention and the patient's tumor cells.

FIG. 3: Schematic representation of multi-chain CAR.

FIG. 4: Schematic of different versions of multi-chain CARs. A.Schematic of the FcεRI receptor. B-C Different versions of multi-chainCARs (csm1 to csm10) comprising a scFv and a CD8 stalk region fused tothe transmembrane domain of FcεRI alpha chain. At least one 41BB, CD28and/or CD3 zeta domains can be fused to a FcεRI alpha, beta and/or gammachain.

FIG. 5: Schematic representation of one example of the method ofengineering human allogenic cells for immunotherapy

FIG. 6: Concentration in cells per milliliter of live CD52-positive orCD52-negative cells after treatment with anti-CD52 antibody (CAMPATH1-H)with complement or controls.

FIG. 7: Comparison of the forward side scatter (FSC) distribution, anindicator of cell size, between TCR-positive and TCR-negative cells, orbetween CD52-positive and CD52-negative cells, and non activated cellsas control.

FIG. 8: Flow cytometry analysis of CD107a expression (marker ofdegranulation) on targeted CD52 and TCRalpha inactivated T cells. CD107expression is analyzed on CD52+TCRαβ+ cells (first column), CD52−TCRαβ−cells (second column), CD52−TCRαβ+ cells (third column) and CD52+TCRαβ−cells (fourth column) before (A) and after incubation with Daudi cells(B); C) represents flow cytometry analysis of T cells furthertransfected with a CAR and incubated with Daudi cells; D) representsflow cytometry analysis of T cells transfected with a CAR but notincubated with Daudi cells and E) represents flow cytometry analysis ofT cells transfected with a CAR and treated to PMA/ionomycin (positivecontrol).

FIG. 9: Deep sequencing analysis of CD52 and TRAC TALE-nucleasespotential off-site targets.

FIG. 10: Analysis of PDCD1 and CTLA-4 genomic locus by T7-endonucleaseassay. Arrows point to digested PCR products.

FIG. 11: Schematic representation of some examples of preTalphaconstructs.

FIG. 12: Flow cytometry analysis of transduction efficiency (% BFP+cells) and activity of the FL, Δ18, Δ48 pTalpha constructs (% CD3surface expression) in TCR alpha inactivated Jurkat cells.

FIG. 13: Schematic representation of a lentiviral construct coding forpTalpha protein (preTCRα).

FIG. 14: A. Representation of the experimental protocol. B. Flowcytometry analysis of TCR alpha/beta, CD3 expression and BFP expressionon TCRalpha inactivated T cells (KO) transduced with eitherBFP-2A-pTalphaΔ48 (KO/Δ48) or control BFP lentiviral vector (KO/BFP)before and after purification. C. Flow cytometry analysis of TCRalpha/beta and CD3 expression on purified TCR alpha inactivated cellstransduced (BFPpos) or not (BFPneg) with BFP-2A-pTalphaΔ48 lentiviralvector. NEP represents non electroporated cells with TRACTALE-nucleases.

FIG. 15: A-B. Flow cytometry analysis of early activation marker CD69(A), late activation marker CD25 (B) expression 24 and 48 hours afterre-activation with anti-CD3/CD28 beads respectively on nonelectroporated cells (NEP) and TCRalpha inactivated cells (KO)transduced with BFP-2A-pTα-Δ48 lentiviral vector (pTα-Δ48),BFP-2A-pTα-Δ48.41BB lentiviral vector (pTα-Δ48.BB) or control BFP vector(BFP). pTα-Δ48 histograms correspond to the signal detected in TCRinactivated cells expressing pTα-Δ48 (BFP+ cells) while the KOhistograms correspond to TCRalpha inactivated cells which do not expresspTα-Δ48 (BFP− cells) pTα-Δ48.BB histograms correspond to the signaldetected in TCR inactivated cells expressing pTα-Δ48.41BB (BFP+ cells)while the KO histograms correspond to TCRalpha inactivated cells whichdo not express pTα-Δ48.41BB (BFP− cells). NEP (non electroporated)histograms correspond to signal detected in non engineered cells. C.Flow cytometry analysis of the size of cells 72 hours afterre-activation with anti-CD3/CD28 beads on non electroporated cells (NEP)and TCRalpha inactivated cells (KO) transduced with BFP-2A-pTα-Δ48lentiviral vector (pTα-Δ48), BFP-2A-pTα-Δ48.41BB lentiviral vector(pTα-Δ48.BB) or control BFP vector (BFP). The values indicated in theupper part of each graph correspond to the geometrical mean of thefluorescence of each population.

FIG. 16: Cell growth analysis of TCR alpha inactivated cells (KO)transduced with pTalpha-Δ48 (pTaΔ48) or control BFP vector (BFP)maintained in IL2 or in IL2 with anti-CD3/CD28 beads at different timepoints (x-axis). The BFP+ cells number is estimated at different timepoints for each condition and the fold induction of these cells (y-axis)was estimated with respect to the value obtained at day 2 postre-activation. The results are obtained from two independent donors. Forthe second donor, cell growth was also determined for cells transducedwith pTalpha-Δ48.41BB (pTa-Δ48.BB) and full-length pTalpha-(pTa-FL).

FIG. 17: Flow cytometry analysis of GFP positive cells on PBMCselectroporated with the five different Cytopulse programs. The upperline corresponds to transfection of 6×10⁶ cells per cuvette, while thelower line corresponds to transfection of 3×10⁶ cells per cuvette.

FIG. 18: Flow cytometry analysis of purified T cell mortality usingviability dye (eFluor-450) and of GFP positive cells among the viablepopulation after electroporation with GFP mRNA, GFP DNA and control pUCDNA. NEP corresponds to cells that were maintained in electroporationbuffer but were not electroporated and NT corresponds to nonelectroporated cells maintained in culture medium.

FIG. 19: Flow cytometry analysis of TCR alpha/beta and CD3 expression onhuman primary T cells following TRAC TALE-nuclease mRNA electroporation(top). Deep sequencing analysis of genomic DNA extracted from humanprimary T cells following TRAC TALE-nuclease mRNA electroporation(bottom).

FIG. 20: A. Flow cytometry analysis of CAR expression (anti F(ab′)2)after electroporation of T cells with or without mRNA encoding a singlechain CAR. B. Flow cytometry analysis of CD107a expression (marker ofdegranulation) on electroporated T cells cocultured with daudi cells.

FIG. 21: A. Representation of mRNA encoding a multi-chain CAR. B. Flowcytometry analysis of CAR expression (anti F(ab′)2) on viable T cellselectroporated with or without a polycistronic mRNA encoding amulti-chain CAR. C. Flow cytometry analysis of CD107a expression (markerof degranulation) on electroporated T cells cocultured with daudi cells.

Table 1: Description of the GR TALE-nucleases and sequences of theTALE-nucleases target sites in the human GR gene.

Table 2: Cleavage activity of the GR TALE-nucleases in yeast. Values arecomprised between 0 and 1. Maximal value is 1.

Table 3: Percentage of targeted mutagenesis at endogenous TALE-nucleasetarget sites in 293 cells.

Table 4: Percentage of targeted mutagenesis at endogenous TALE-nucleasetarget sites in primary T lymphocytes.

Table 5: Description of the CD52, TRAC and TRBC TALE-nucleases andsequences of the TALE-nucleases target sites in the human correspondinggenes.

Table 6: Additional target sequences for TRAC and CD52 TALE-nucleases.

Table 7: Percentage of indels for TALE-nuclease targeting CD52_T02,TRAC_T01, TRBC_T01 and TRBC_T02 targets.

Table 8: Percentages of CD52-negative, TCR-negative and CD52/TCR-doublenegative T lymphocytes after transfection of correspondingTALE-nuclease-expressing polynucleotides.

Table 9: Percentages of TCR-negative T lymphocytes after transfection ofTRBC TALE-nuclease-expressing polynucleotides.

Table 10: Description of the CTLA4 and PDCD1 TALE-nucleases andsequences of the TALE-nucleases target sites in the human correspondinggenes.

Table 11: Description of a subset of pTalpha constructs.

Table 12: Activity of the different pTalpha constructs in Jurkat TCRalpha inactivated cell. Activity was measured by flow cytometry analysisof CD3 expression on jurkat TCR alpha inactivated cell transfected withthe different preTalpha constructs.

Table 13: Different cytopulse programs used to determine the minimalvoltage required for electroporation in PBMC derived T-cells.

Table 14: Cytopulse program used to electroporate purified T-cells.

DETAILED DESCRIPTION OF THE INVENTION

Unless specifically defined herein, all technical and scientific termsused have the same meaning as commonly understood by a skilled artisanin the fields of gene therapy, biochemistry, genetics, and molecularbiology.

All methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the present invention,with suitable methods and materials being described herein. Allpublications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Incase of conflict, the present specification, including definitions, willprevail. Further, the materials, methods, and examples are illustrativeonly and are not intended to be limiting, unless otherwise specified.

The practice of the present invention will employ, unless otherwiseindicated, conventional techniques of cell biology, cell culture,molecular biology, transgenic biology, microbiology, recombinant DNA,and immunology, which are within the skill of the art. Such techniquesare explained fully in the literature. See, for example, CurrentProtocols in Molecular Biology (Frederick M. AUSUBEL, 2000, Wiley andson Inc, Library of Congress, USA); Molecular Cloning: A LaboratoryManual, Third Edition, (Sambrook et al, 2001, Cold Spring Harbor, N.Y.:Cold Spring Harbor Laboratory Press); Oligonucleotide Synthesis (M. J.Gait ed., 1984); Mullis et al. U.S. Pat. No. 4,683,195; Nucleic AcidHybridization (B. D. Harries & S. J. Higgins eds. 1984); TranscriptionAnd Translation (B. D. Hames & S. J. Higgins eds. 1984); Culture OfAnimal Cells (R. I. Freshney, Alan R. Liss, Inc., 1987); ImmobilizedCells And Enzymes (IRL Press, 1986); B. Perbal, A Practical Guide ToMolecular Cloning (1984); the series, Methods In ENZYMOLOGY (J. Abelsonand M. Simon, eds.-in-chief, Academic Press, Inc., New York),specifically, Vols. 154 and 155 (Wu et al. eds.) and Vol. 185, “GeneExpression Technology” (D. Goeddel, ed.); Gene Transfer Vectors ForMammalian Cells (J. H. Miller and M. P. Calos eds., 1987, Cold SpringHarbor Laboratory); Immunochemical Methods In Cell And Molecular Biology(Mayer and Walker, eds., Academic Press, London, 1987); Handbook OfExperimental Immunology, Volumes I-IV (D. M. Weir and C. C. Blackwell,eds., 1986); and Manipulating the Mouse Embryo, (Cold Spring HarborLaboratory Press, Cold Spring Harbor, N.Y., 1986).

In a general aspect, the present invention relates to methods for newadoptive immunotherapy strategies in treating cancer and infections.

Non Alloreactive and Immunosuppressive Resistant T Cells:

In a particular aspect, the present invention relates to a method ofengineering T-cells, especially for immunotherapy. In particular thismethod comprises:

-   -   (a) modifying T-cells by inactivating at least:        -   A first gene expressing a target for an immunosuppressive            agent, and        -   A second gene encoding a component of the T-cell receptor            (TCR)    -   (b) Expanding said cells, optionally in presence of said        immunosuppressive agent.

An immunosuppressive agent is an agent that suppresses immune functionby one of several mechanisms of action. In other words, animmunosuppressive agent is a role played by a compound which isexhibited by a capability to diminish the extent and/or voracity of animmune response. As non limiting example, an immunosuppressive agent canbe a calcineurin inhibitor, a target of rapamycin, an interleukin-2α-chain blocker, an inhibitor of inosine monophosphate dehydrogenase, aninhibitor of dihydrofolic acid reductase, a corticosteroid or animmunosuppressive antimetabolite. Classical cytotoxic immunosuppressantsact by inhibiting DNA synthesis. Others may act through activation ofT-cells or by inhibiting the activation of helper cells. The methodaccording to the invention allows conferring immunosuppressiveresistance to T cells for immunotherapy by inactivating the target ofthe immunosuppressive agent in T cells. As non limiting examples,targets for immunosuppressive agent can be a receptor for animmunosuppressive agent such as: CD52, glucocorticoid receptor (GR), aFKBP family gene member and a cyclophilin family gene member.

In a particular embodiment, the genetic modification step of the methodrelies on the inactivation of one gene selected from the groupconsisting of CD52, GR, TCR alpha and TCR beta. In another embodiment,the genetic modification step of the method relies on the inactivationof two genes selected from the group consisting of CD52 and GR, CD52 andTCR alpha, CDR52 and TCR beta, GR and TCR alpha, GR and TCR beta, TCRalpha and TCR beta. In another embodiment, the genetic modification stepof the method relies on the inactivation of more than two genes. Thegenetic modification is preferably operated ex-vivo.

By inactivating a gene it is intended that the gene of interest is notexpressed in a functional protein form. In particular embodiment, thegenetic modification of the method relies on the expression, in providedcells to engineer, of one rare-cutting endonuclease such that saidrare-cutting endonuclease specifically catalyzes cleavage in onetargeted gene thereby inactivating said targeted gene. The nucleic acidstrand breaks caused by the rare-cutting endonuclease are commonlyrepaired through the distinct mechanisms of homologous recombination ornon-homologous end joining (NHEJ). However, NHEJ is an imperfect repairprocess that often results in changes to the DNA sequence at the site ofthe cleavage. Mechanisms involve rejoining of what remains of the twoDNA ends through direct re-ligation (Critchlow and Jackson 1998) or viathe so-called microhomology-mediated end joining (Ma, Kim et al. 2003).Repair via non-homologous end joining (NHEJ) often results in smallinsertions or deletions and can be used for the creation of specificgene knockouts. Said modification may be a substitution, deletion, oraddition of at least one nucleotide. Cells in which a cleavage-inducedmutagenesis event, i.e a mutagenesis event consecutive to an NHEJ event,has occurred can be identified and/or selected by well-known method inthe art. In a particular embodiment, said method to engineer cellscomprises at least one of the following steps:

-   -   (a) Providing a T-cell, preferably from a cell culture or from a        blood sample;    -   (b) Selecting a gene in said T-cell expressing a target for an        immunosuppressive agent;    -   (c) Introducing into said T-cell a rare-cutting endonuclease        able to selectively inactivate by DNA cleavage, preferably by        double-strand break respectively:        -   said gene encoding a target for said immunosuppressive            agent, and        -   at least one gene encoding a component of the T-cell            receptor (TCR).    -   (d) Expanding said cells, optionally in presence of said        immunosuppressive agent.

In a more preferred embodiment, said method comprises:

-   -   (a) Providing a T-cell, preferably from a cell culture or from a        blood sample;    -   (b) Selecting a gene in said T-cell expressing a target for an        immunosuppressive agent;    -   (c) Transforming said T cell with nucleic acid encoding a        rare-cutting endonuclease able to selectively inactivate by DNA        cleavage, preferably by double-strand break respectively:        -   said gene encoding a target for said immunosuppressive            agent, and        -   at least one gene encoding a component of the T-cell            receptor (TCR);    -   (d) Expressing said rare-cutting endonucleases into said        T-cells;    -   (e) Sorting the transformed T-cells, which do not express TCR on        their cell surface;    -   (f) Expanding said cells, optionally in presence of said        immunosuppressive agent.

In particular embodiment, said rare-cutting endonuclease specificallytargets one gene selected from the group consisting of CD52, GR, TCRalpha and TCR beta. In another embodiment, the genetic modification ofthe method relies on the expression, in provided cells to engineer, oftwo rare-cutting endonucleases such that said each of the tworare-cutting endonucleases specifically and respectively catalyzescleavage in each of the pairs of genes selected from the groupconsisting of CD52 and GR, CD52 and TCR alpha, CDR52 and TCR beta, GRand TCR alpha, GR and TCR beta, TCR alpha and TCR beta, therebyinactivating said targeted genes. In another embodiment, more than tworare-cutting endonucleases can be expressed in cells to engineer inorder to target and/or inactivate more than two genes.

In another embodiment, said gene of step (b), specific for animmunosuppressive treatment, is CD52 and the immunosuppressive treatmentof step (d) or (e) comprises a humanized antibody targeting CD52antigen.

In another embodiment, said gene of step (b), specific for animmunosuppressive treatment, is a glucocorticoid receptor (GR) and theimmunosuppressive treatment of step d) or (e) comprises a corticosteroidsuch as dexamethasone.

In another embodiment, said target gene of step (b), specific for animmunosuppressive treatment, is a FKBP family gene member or a variantthereof and the immunosuppressive treatment of step (d) or (e) comprisesFK506 also known as Tacrolimus or fujimycin. In another embodiment, saidFKBP family gene member is FKBP12 or a variant thereof.

In another embodiment, said gene of step (b), specific for animmunosuppressive treatment, is a cyclophilin family gene member or avariant thereof and the immunosuppressive treatment of step (d) or (e)comprises cyclosporine.

In another embodiment, said rare-cutting endonuclease can be ameganuclease, a Zinc finger nuclease or a TALE-nuclease. In a preferredembodiment, said rare-cutting endonuclease is a TALE-nuclease. ByTALE-nuclease is intended a fusion protein consisting of a DNA-bindingdomain derived from a Transcription Activator Like Effector (TALE) andone nuclease catalytic domain to cleave a nucleic acid target sequence.(Boch, Scholze et al. 2009; Moscou and Bogdanove 2009) (Deng, Yan et al.2012; Mak, Bradley et al. 2012) (Christian, Cermak et al. 2010; Cermak,Doyle et al. 2011; Geissler, Scholze et al. 2011; Huang, Xiao et al.2011; Li, Huang et al. 2011; Mahfouz, Li et al. 2011; Miller, Tan et al.2011; Morbitzer, Romer et al. 2011; Mussolino, Morbitzer et al. 2011;Sander, Cade et al. 2011; Tesson, Usal et al. 2011; Weber, Gruetzner etal. 2011; Zhang, Cong et al. 2011; Li, Piatek et al. 2012; Mahfouz, Liet al. 2012) In the present invention new TALE-nucleases have beendesigned for precisely targeting relevant genes for adoptiveimmunotherapy strategies.

Preferred TALE-nucleases according to the invention are thoserecognizing and cleaving the target sequence selected from the groupconsisting of:

-   -   SEQ ID NO: 1 to 6 (GR),    -   SEQ ID NO: 37, 57 to 60 (TCRalpha),    -   SEQ ID NO: 38 or 39 (TCRbeta), and    -   SEQ ID NO: 40, 61 to 65 (CD52)

Said TALE-nucleases preferably comprise a polypeptide sequence selectedfrom SEQ ID NO: 7 to SEQ ID NO: 18 and SEQ ID NO: 41 to SEQ ID NO: 48,in order to cleave the respective target sequences SEQ ID NO: 1 to 6 andSEQ ID NO: 37 to 40.

In another embodiment, additional catalytic domain can be furtherintroduced into the cell with said rare-cutting endonuclease to increasemutagenesis in order to enhance their capacity to inactivate targetedgenes. In particular, said additional catalytic domain is a DNA endprocessing enzyme. Non limiting examples of DNA end-processing enzymesinclude 5-3′ exonucleases, 3-5′ exonucleases, 5-3′ alkalineexonucleases, 5′ flap endonucleases, helicases, hosphatase, hydrolasesand template-independent DNA polymerases. Non limiting examples of suchcatalytic domain comprise of a protein domain or catalytically activederivate of the protein domain selected from the group consisting ofhExoI (EXO1_HUMAN), Yeast ExoI (EXO1_YEAST), E. coli ExoI, Human TREX2,Mouse TREX1, Human TREX1, Bovine TREX1, Rat TREX1, TdT (terminaldeoxynucleotidyl transferase) Human DNA2, Yeast DNA2 (DNA2_YEAST). In apreferred embodiment, said additional catalytic domain has a3′-5′-exonuclease activity, and in a more preferred embodiment, saidadditional catalytic domain is TREX, more preferably TREX2 catalyticdomain (WO2012/058458). In another preferred embodiment, said catalyticdomain is encoded by a single chain TREX polypeptide. Said additionalcatalytic domain may be fused to a nuclease fusion protein or chimericprotein according to the invention optionally by a peptide linker.

Endonucleolytic breaks are known to stimulate the rate of homologousrecombination. Thus, in another embodiment, the genetic modificationstep of the method further comprises a step of introduction into cellsan exogeneous nucleic acid comprising at least a sequence homologous toa portion of the target nucleic acid sequence, such that homologousrecombination occurs between the target nucleic acid sequence and theexogeneous nucleic acid. In particular embodiments, said exogenousnucleic acid comprises first and second portions which are homologous toregion 5′ and 3′ of the target nucleic acid sequence, respectively. Saidexogenous nucleic acid in these embodiments also comprises a thirdportion positioned between the first and the second portion whichcomprises no homology with the regions 5′ and 3′ of the target nucleicacid sequence. Following cleavage of the target nucleic acid sequence, ahomologous recombination event is stimulated between the target nucleicacid sequence and the exogenous nucleic acid. Preferably, homologoussequences of at least 50 bp, preferably more than 100 bp and morepreferably more than 200 bp are used within said donor matrix.Therefore, the exogenous nucleic acid is preferably from 200 bp to 6000bp, more preferably from 1000 bp to 2000 bp. Indeed, shared nucleic acidhomologies are located in regions flanking upstream and downstream thesite of the break and the nucleic acid sequence to be introduced shouldbe located between the two arms.

In particular, said exogenous nucleic acid successively comprises afirst region of homology to sequences upstream of said cleavage, asequence to inactivate one targeted gene selected from the groupconsisting of CD52, GR, TCR alpha and TCR beta and a second region ofhomology to sequences downstream of the cleavage. Said polynucleotideintroduction step can be simultaneous, before or after the introductionor expression of said rare-cutting endonuclease. Depending on thelocation of the target nucleic acid sequence wherein break event hasoccurred, such exogenous nucleic acid can be used to knock-out a gene,e.g. when exogenous nucleic acid is located within the open readingframe of said gene, or to introduce new sequences or genes of interest.Sequence insertions by using such exogenous nucleic acid can be used tomodify a targeted existing gene, by correction or replacement of saidgene (allele swap as a non-limiting example), or to up- or down-regulatethe expression of the targeted gene (promoter swap as non-limitingexample), said targeted gene correction or replacement. In preferredembodiment, inactivation of genes from the group consisting of CD52, GR,TCR alpha and TCR beta can be done at a precise genomic locationtargeted by a specific TALE-nuclease, wherein said specificTALE-nuclease catalyzes a cleavage and wherein said exogenous nucleicacid successively comprising at least a region of homology and asequence to inactivate one targeted gene selected from the groupconsisting of CD52, GR, TCR alpha and TCR beta which is integrated byhomologous recombination. In another embodiment, several genes can be,successively or at the same time, inactivated by using severalTALE-nucleases respectively and specifically targeting one defined geneand several specific polynucleotides for specific gene inactivation.

By additional genomic modification step, can be intended also theinactivation of another gene selected from the group consisting of CD52,GR, TCR alpha and TCR beta. As mentioned above, said additional genomicmodification step can be an inactivation step comprising:

-   -   (a) introducing into said cells at least one rare-cutting        endonuclease such that said rare-cutting endonuclease        specifically catalyzes cleavage in one targeted sequence of the        genome of said cell.    -   (b) Optionally introducing into said cells a exogenous nucleic        acid successively comprising a first region of homology to        sequences upstream of said cleavage, a sequence to be inserted        in the genome of said cell and a second region of homology to        sequences downstream of said cleavage,        wherein said introduced exogenous nucleic acid inactivates a        gene and integrates at least one exogenous polynucleotide        sequence encoding at least one recombinant protein of interest.        In another embodiment, said exogenous polynucleotide sequence is        integrated within a gene selected from the group consisting of        CD52, GR, TCR alpha and TCR beta.

In particular embodiment said method to engineer cell further comprisesan additional genomic modification step. By additional genomicmodification step, can be intended the introduction into cells toengineer of one protein of interest. Said protein of interest can be, asnon limiting examples, pTalpha or functional variant thereof, a ChimericAntigen Receptor (CAR), a multi-chain CAR, a bispecific antibody orrare-cutting endonuclease targeting PDCD1 or CTLA-4 as described in thepresent disclosure.

The invention also relates to TALE-nucleases. Generally, the inventionrelates to TALE-nuclease comprising:

-   -   (a) A Transcription Activator-Like Effector (TALE) DNA binding        domain that has been engineered to bind a target sequence within        genes selected from the group consisting of CD52, GR, TCR alpha        and TCR beta;    -   (b) A cleavage domain or a cleavage half-domain.

Preferred TALE-nucleases according to the invention are thoserecognizing and cleaving the target sequence selected from the groupconsisting of:

-   -   SEQ ID NO: 1 to 6 (GR),    -   SEQ ID NO: 37, 57 to 60 (TCRalpha),    -   SEQ ID NO: 38 or 39 (TCRbeta), and    -   SEQ ID NO: 40, 61 to 65 (CD52)

Said TALE-nucleases preferably comprise a polypeptide sequence selectedfrom SEQ ID NO: 7 to SEQ ID NO: 18 and SEQ ID NO: 41 to SEQ ID NO: 48,in order to cleave the respective target sequences SEQ ID NO: 1 to 6 andSEQ ID NO: 37 to 40.

Because some variability may arise from the genomic data from whichthese polypeptides derive, and also to take into account the possibilityto substitute some of the amino acids present in these polypeptideswithout significant loss of activity (functional variants), theinvention encompasses polypeptides variants of the above polypeptidesthat share at least 70%, preferably at least 80%, more preferably atleast 90% and even more preferably at least 95% identity with thesequences provided in this patent application.

The present invention is thus drawn to polypeptides comprising apolypeptide sequence that has at least 70%, preferably at least 80%,more preferably at least 90%, 95% 97% or 99% sequence identity withamino acid sequence selected from the group consisting of SEQ ID NO:7 toSEQ ID NO: 18 and SEQ ID NO: 41 to SEQ ID NO: 48.

Are also comprised in the scope of the present invention,polynucleotides, vectors encoding the above described rare-cuttingendonucleases according to the invention.

In the scope of the present invention are also encompassed isolatedcells or cell lines susceptible to be obtained by said method toengineer cells, in particular T cells, in which at least one geneselected from the group consisting of CD52, GR, TCR alpha and TCR betahas been inactivated. Preferably, two genes selected from the groupconsisting of CD52 and GR, CD52 and TCR alpha, CDR52 and TCR beta, GRand TCR alpha, GR and TCR beta, TCR alpha and TCR beta have beeninactivated.

According to the invention, those genes are preferably inactivated by atleast one rare-cutting endonuclease. It has been shown by the inventorsthat the use of TALE-nucleases was particularly advantageous to achievedouble inactivation in T-cells. The invention encompasses an isolatedT-cell comprising at least two polynucleotides, said polynucleotidesencoding at least a first and second TALE-nucleases, preferably thefirst TALE-nuclease being directed against a gene encoding TCR and thesecond being directed against a gene encoding a receptor for animmunosuppressive agent, such as CD52 or GR.

In another embodiment, said isolated cell further comprises oneadditional genomic modification. In another embodiment, said additionalgenomic modification is the integration of at least one exogenouspolynucleotide sequence. In another embodiment, said exogenous sequenceis integrated into one gene selected from the group consisting of CD52,GR, TCR alpha and TCR beta.

PreTalpha

In another aspect, the invention relates to a method of expanding TCRalpha deficient T-cell comprising introducing into said T-cell pTalpha(also named preTCRα) or a functional variant thereof and expanding saidcells, optionally through stimulation of the CD3 complex. In a preferredembodiment, the method comprises:

-   -   a) Transforming said cells with nucleic acid encoding at least a        fragment of pTalpha to support CD3 surface expression    -   b) Expressing said pTalpha into said cells    -   c) Expanding said cells optionally, optionally through        stimulation of the CD3 complex.

The invention also relates to a method of preparing T-cells forimmunotherapy comprising steps of the method for expansion for T-cell.

In particular embodiment, the pTalpha polynucleotide sequence can beintroduced randomly or else through homologous recombination, inparticular the insertion could be associated with the inactivation ofthe TCRalpha gene.

According to the invention, different functional variants of pTalpha areused. A “functional variant” of the peptide refers to a moleculesubstantially similar to either the entire peptide or a fragmentthereof. A “fragment” of the pTalpha or functional variant thereof ofthe present Invention, refers to any subset of the molecule, that is, ashorter peptide. Preferred pTalpha or functional variants can be fulllength pTalpha or a C-terminal truncated pTalpha version. C-terminaltruncated pTalpha lacks in C-terminal end one or more residues. As nonlimiting examples, C-terminal truncated pTalpha version lacks 18, 48,62, 78, 92, 110 or 114 residues from the C-terminus of the protein (SEQID NO: 107 to SEQ ID NO: 114). Moreover, amino acid sequence variants ofthe peptide can be prepared by mutations in the DNA which encodes thepeptide. Such functional variants include, for example, deletions from,or insertions or substitutions of, residues within the amino acidsequence. Any combination of deletion, insertion, and substitution mayalso be made to arrive at the final construct, provided that the finalconstruct possesses the desired activity, in particular the restorationof a functional CD3 complex. In preferred embodiment, at least onemutation is introduced in the different pTalpha versions as describedabove to affect dimerization. As non limiting example, mutated residuecan be at least W46R, D22A, K24A, R102A or R117A of the human pTalphaprotein or aligned positions using CLUSTALW method on pTalpha family orhomologue member. Preferably pTalpha or variant thereof as describedabove comprise the mutated residue W46R (SEQ ID NO:123) or the mutatedresidues D22A, K24A, R102A and R117A (SEQ ID NO: 124). In particularembodiment, said pTalpha or variants are also fused to asignal-transducing domain such as CD28, OX40, ICOS, CD27, CD137 (4-1BB)and CD8 as non limiting examples (SEQ ID NO: 115 to SEQ ID NO: 120). Theextracellular domain of pTalpha or variants as described above can befused to a fragment of the TCRalpha protein, particularly thetransmembrane and intracellular domain of TCRalpha (SEQ ID NO: 122).pTalpha variants can also be fused to the intracellular domain ofTCRalpha (SEQ ID NO:121).

In another embodiment, said pTalpha versions are fused to anextracellular ligand-binding domain and more preferably pTalpha orfunctional variant thereof is fused to a single chain antibody fragment(scFV) comprising the light (V_(L)) and the heavy (V_(H)) variablefragment of a target antigen specific monoclonal antibody joined by aflexible linker. As a non limiting example, amino acid sequence ofpTalpha or functional variant thereof is selected from the groupconsisting of SEQ ID NO: 107 to SEQ ID NO: 124.

Because some variability may arise from the genomic data from whichthese polypeptides derive, and also to take into account the possibilityto substitute some of the amino acids present in these polypeptideswithout significant loss of activity (functional variants), theinvention encompasses polypeptides variants of the above polypeptidesthat share at least 70%, preferably at least 80%, more preferably atleast 90% and even more preferably at least 95% identity with thesequences provided in this patent application.

The present invention is thus drawn to polypeptides comprising apolypeptide sequence that has at least 70%, preferably at least 80%,more preferably at least 90%, 95% 97% or 99% sequence identity withamino acid sequence selected from the group consisting of SEQ ID NO:107to SEQ ID NO: 124.

By TCR alpha deficient T cell is intended an isolated T cell that lacksexpression of a functional TCR alpha chain. This may be accomplished bydifferent means, as non limiting examples, by engineering a T cell suchthat it does not express any functional TCR alpha on its cell surface orby engineering a T cell such that it produces very little functional TCRalpha chain on its surface or by engineering a T cell to express mutatedor truncated form of TCR alpha chain.

TCR alpha deficient cells can no longer be expanded through CD3 complex.Thus, to overcome this problem and to allow proliferation of TCR alphadeficient cells, pTalpha or functional variant thereof is introducedinto said cells, thus restoring a functional CD3 complex. In a preferredembodiment, the method further comprises introducing into said T cellsrare-cutting endonucleases able to selectively inactivate by DNAcleavage one gene encoding one component of the T-cell receptor (TCR).In particular embodiment, said rare-cutting endonuclease is aTALE-nucleases. As non limiting examples, TALE-nuclease is directedagainst one of the gene target sequences of TCRalpha selected from thegroup consisting of SEQ ID NO: 37 and SEQ ID NO: 57 to 60. Preferably,TALE-nucleases are selected from the group consisting of SEQ ID NO: 41and SEQ ID NO: 42.

In particular embodiment said method for expansion of TCR alphadeficient T-cells comprises an additional genomic modification step. Byadditional genomic modification step, can be intended the introductioninto cells to engineer of one protein of interest. Said protein ofinterest can be, as non limiting examples, a Chimeric Antigen Receptor(CAR), particularly CAR comprising amino acid sequence SEQ ID NO: 73, amulti-chain CAR, particularly multi-chain CAR comprising amino acidsequence SEQ ID NO: 125 a bispecific antibody, rare-cuttingendonucleases targeting PDCD1 or CTLA-4, particularly targeting nucleicacid sequence SEQ ID NO: 74 to SEQ ID NO: 78 or a rare-cuttingendonuclease targeting a target for immunosuppressive agent as describedin the present disclosure.

Are also encompassed in the present invention polypeptides encodingpTalpha, particularly functional variants described above. In apreferred embodiment the invention relates to a pTalpha or functionalvariant thereof fused to a signal transducing domain such as CD28, OX40,ICOS, CD137 and CD8. More particularly, the invention relates to pTalphafunctional variant comprising amino acid sequence selected form thegroup consisting of SEQ ID NO: 107 to SEQ ID NO: 124. Are alsoencompassed in the present invention polynucleotides, vectors encodingpTalpha or functional variants thereof described above.

In the scope of the present invention are also encompassed isolatedcells or cell lines susceptible to be obtained by said method. Inparticular said isolated cells or cell lines are obtained by introducinginto said cells a pTalpha or a functional variant thereof to support CD3surface expression. In a preferred embodiment, said isolated cell orcell line are further genetically modified by inactivating TCRalphagene. This gene is preferably inactivating by at least one rare-cuttingendonuclease. In a preferred embodiment said rare-cutting endonucleaseis TALE-nuclease.

Multi-Chain Chimeric Antigen Receptor (CAR)

In another embodiment, the invention relates to a multi-chain chimericantigen receptor (CAR) particularly adapted to the production andexpansion of engineered T-cells of the present invention. Themulti-chain CAR comprising at least two of the following components:

-   -   a) one polypeptide comprising the transmembrane domain of FcεRI        alpha chain and an extracellular ligand-binding domain,    -   b) one polypeptide comprising a part of N- and C-terminal        cytoplasmic tail and the transmembrane domain of FcεRI beta        chain and/or    -   c) two polypeptides comprising each a part of intracytoplasmic        tail and the transmembrane domain of FcεRI gamma chain, whereby        different polypeptides multimerize together spontaneously to        form dimeric, trimeric or tetrameric CAR.

One example of tetrameric CAR is illustrated in FIG. 3. Differentversions of multichain CARs are represented in FIG. 4. One example ofmulti-chain CAR comprises amino acid sequence SEQ ID NO: 125. The term“a part of” used herein refers to any subset of the molecule, that is ashorter peptide. Alternatively, amino acid sequence functional variantsof the polypeptide can be prepared by mutations in the DNA which encodesthe polypeptide. Such functional variants include, for example,deletions from, or insertions or substitutions of, residues within theamino acid sequence. Any combination of deletion, insertion, andsubstitution may also be made to arrive at the final construct, providedthat the final construct possesses the desired activity, especially toexhibit a specific anti-target cellular immune activity.

In a preferred embodiment, said extracellular ligand-binding domain is ascFv. Other binding domain than scFv can also be used for predefinedtargeting of lymphocytes, such as camelid single-domain antibodyfragments or receptor ligands like a vascular endothelial growth factorpolypeptide, an integrin-binding peptide, heregulin or an IL-13 mutein,antibody binding domains, antibody hypervariable loops or CDRs as nonlimiting examples.

In a preferred embodiment said polypeptide of a) further comprises astalk region between said extracellular ligand-binding domain and saidtransmembrane domain. The term “stalk region” used herein generallymeans any oligo- or polypeptide that functions to link the transmembranedomain to the extracellular ligand-binding domain. In particular, stalkregion are used to provide more flexibility and accessibility for theextracellular ligand-binding domain. A stalk region may comprise up to300 amino acids, preferably 10 to 100 amino acids and most preferably 25to 50 amino acids. Stalk region may be derived from all or part ofnaturally occurring molecules, such as from all or part of theextracellular region of CD8, CD4 or CD28, or from all or part of anantibody constant region. Alternatively the stalk region may be asynthetic sequence that corresponds to a naturally occurring stalksequence, or may be an entirely synthetic stalk sequence.

In a preferred embodiment, said polypeptide of a), b) and/or c) furthercomprises at least one signal-transducing domain. In a most preferredembodiment, said signal-transducing domain is selected from the groupconsisting of CD28, OX40, ICOS, CD137 and CD8.

In a preferred embodiment, said C-terminal cytoplasmic tail of FcεRIalpha, beta and/or gamma chain fragment further comprisesTNFR-associated Factor 2 (TRAF2) binding motifs. In a most preferredembodiment, said C-terminal cytoplasmic tail of FcεRI alpha, beta and/orgamma chain is replaced by intracytoplasmic tail of costimulatory TNFRmember family. Cytoplasmic tail of costimulatory TNFR family membercontains TRAF2 binding motifs consisting of the major conserved motif(P/S/A)X(Q/E)E) or the minor motif (PXQXXD), wherein X is any aminoacid. TRAF proteins are recruited to the intracellular tails of manyTNFRs in response to receptor trimerization.

In another preferred embodiment said intracytoplasmic domain of FcεRIalpha, beta and/or gamma chain is replaced by intracytoplasmic domain ofTCR zeta chain (also named CD3 zeta). In another preferred embodiment,said intracytoplasmic domain of FcεRI alpha, beta and/or gamma chaincomprises at least one additional immunoreceptor tyrosine-basedactivation motif (ITAM). ITAMs are well defined signaling motifs foundin the intracytoplasmic tail of a variety of receptors that serve asbinding sites for syk/zap70 class tyrosine kinases. Examples of ITAMused in the invention include those derived from TCRzeta, FCRgamma,FCRbeta, CD3gamma, CD3delta, CD3epsilon, CD5, CD22, CD79a, CD79b, andCD66d.

As non limiting example, different versions of multi-chain CAR areillustrated in FIG. 4.

In a preferred embodiment the multi-chain CAR comprise the amino acidsequence SEQ ID NO: 125. The present invention relates to polypeptidescomprising a polypeptide sequence that has at least 70%, preferably atleast 80%, more preferably at least 90%, 95% 97% or 99% sequenceidentity with amino acid sequence selected from the group consisting ofSEQ ID NO: 125.

Are also comprised in the scope of the present invention,polynucleotides, vectors encoding the above described multi-chain CARaccording to the invention.

In encompassed particular embodiment, the invention relates to a methodof preparing T-cells for immunotherapy comprising introducing into saidT-cells the different polypeptides composing said multi-chain CAR andexpanding said cells.

In another embodiment, said method further comprises a step ofgenetically modifying said cells by inactivating at least one geneexpressing one component of the TCR and/or a target for animmunosuppressive agent. In a preferred embodiment, said gene isselected from the group consisting of TCRalpha, TCRbeta, CD52 and GR. Ina preferred embodiment said method further comprises introducing intosaid T cells a rare-cutting endonuclease able to selectively inactivateby DNA cleavage said genes. In a more preferred embodiment saidrare-cutting endonuclease is TALE-nuclease. Preferred TALE-nucleasesaccording to the invention are those recognizing and cleaving the targetsequence selected from the group consisting of: SEQ ID NO: 1 to 6 (GR),SEQ ID NO: 37, 57 to 60 (TCRalpha), SEQ ID NO: 38 or 39 (TCRbeta), andSEQ ID NO: 40, SEQ ID NO: 61 to SEQ ID NO: 65 (CD52).

In particular embodiment said method further comprises an additionalgenomic modification step. By additional genomic modification step, canbe intended the introduction into cells to engineer of one protein ofinterest. Said protein of interest can be, as non limiting examples abispecific antibody, rare-cutting endonuclease targeting PDCD1 orCTLA-4, a pTalpha or a functional variant thereof as described in thepresent disclosure.

The present invention also relates isolated cells or cell linessusceptible to be obtained by said method to engineer cells. Inparticular said isolated cell comprises exogenous polynucleotidesequences encoding polypeptides composing said multi-chain CAR.

Inactivated PDCD1 or CTLA4 T Cells

One another approach to activating therapeutic antitumor immunity is theblockade of immune checkpoints. Immunity response is regulated by thecounterbalancing of stimulatory and inhibitory signal. The expression ofimmune-checkpoint proteins can be dysregulated by tumours and can be animportant immune resistance mechanism. Negative regulators of T-cellfunction include molecules such as CTLA-4, a key negative regulatorymolecule that down-regulates pathways of T-cell activation andprogrammed death-1 (PD1) also known as PDCD1, a transmembrane receptorup-regulated on activated T cells that when bound to its ligand(programmed death ligand-1, PD-L1) leads to decreased cytokineproduction and proliferation of T cells (Pardoll 2012). Thus,antagonists of inhibitory signal result in the amplification ofantigen-specific T-cell response.

Thus the present invention relates to a method of engineering T-cells,especially for immunotherapy, comprising genetically modifying T-cellsby inactivating at least one protein involved in the immune check-point,in particular PDCD1 and/or CTLA-4.

In a particular embodiment, the method comprises one of the followingsteps:

-   -   (a) providing a T cell,    -   (b) introducing into said T cell a rare-cutting endonuclease        able to selectively inactivate by DNA cleavage PDCD1 gene or        CTLA-4 gene; and    -   (c) expanding said cells.

In a preferred embodiment, said rare-cutting endonuclease is aTALE-nuclease. In the present invention new TALE-nucleases have beendesigned for precisely targeting relevant genes for adoptiveimmunotherapy strategies. Preferred TALE-nucleases according to theinvention are those recognizing and cleaving the target sequenceselected from the group consisting of SEQ ID NO: 77 and SEQ ID NO: 78(PDCD-1), SEQ ID NO: 74 to SEQ ID NO: 76 (CTLA-4). The present inventionalso relates to TALE-nucleases polypeptides which comprise an amino acidsequence selected from the group consisting of SEQ ID NO: 79 to SEQ IDNO: 88.

The present invention also relates to polypeptides comprising an aminoacid sequence that has at least 70%, preferably at least 80%, morepreferably at least 90%, 95% 97% or 99% sequence identity with aminoacid sequence selected from the group consisting of SEQ ID NO: 79 to SEQID NO: 88. Are also comprised in the scope of the present invention,polynucleotides, vectors encoding the above described rare-cuttingendonucleases according to the invention. This method can be associatedwith any one of the different methods described in the presentdisclosure.

Bispecific Antibodies

According to a further embodiment, engineered T cells obtained by thedifferent methods as previously described can be further exposed withbispecific antibodies. Said T-cells could be exposed to bispecificantibodies ex vivo prior to administration to a patient or in vivofollowing administration to a patient. Said bispecific antibodiescomprise two variable regions with distinct antigen properties thatallow bringing the engineered cells into proximity to a target antigen.As a non limiting example, said bispecific antibody is directed againsta tumor marker and lymphocyte antigen such as CD3 and has the potentialto redirect and activate any circulating T cells against tumors.

Delivery Methods

The different methods described above involve introducing pTalpha orfunctional variants thereof, rare cutting endonuclease, TALE-nuclease,CAR or multi-chain CAR optionally with DNA-end processing enzyme orexogenous nucleic acid into a cell.

As non-limiting example, said pTalpha or functional variant thereof,rare cutting endonucleases, TALE-nucleases, CAR or multi-chain CARoptionally with DNA-end processing enzyme or exogenous nucleic acid canbe introduced as transgenes encoded by one or as different plasmidicvectors. Different transgenes can be included in one vector whichcomprises a nucleic acid sequence encoding ribosomal skip sequence suchas a sequence encoding a 2A peptide. 2A peptides, which were identifiedin the Aphthovirus subgroup of picornaviruses, causes a ribosomal “skip”from one codon to the next without the formation of a peptide bondbetween the two amino acids encoded by the codons (see Donnelly et al.,J. of General Virology 82: 1013-1025 (2001); Donnelly et al., J. of Gen.Virology 78: 13-21 (1997); Doronina et al., Mol. And. Cell. Biology28(13): 4227-4239 (2008); Atkins et al., RNA 13: 803-810 (2007)). By“codon” is meant three nucleotides on an mRNA (or on the sense strand ofa DNA molecule) that are translated by a ribosome into one amino acidresidue. Thus, two polypeptides can be synthesized from a single,contiguous open reading frame within an mRNA when the polypeptides areseparated by a 2A oligopeptide sequence that is in frame. Such ribosomalskip mechanisms are well known in the art and are known to be used byseveral vectors for the expression of several proteins encoded by asingle messenger RNA. As non-limiting example, in the present invention,2A peptides have been used to express into the cell the rare-cuttingendonuclease and a DNA end-processing enzyme or the differentpolypeptides of the multi-chain CAR.

Said plasmid vector can contain a selection marker which provides foridentification and/or selection of cells which received said vector.

Polypeptides may be synthesized in situ in the cell as a result of theintroduction of polynucleotides encoding said polypeptides into thecell. Alternatively, said polypeptides could be produced outside thecell and then introduced thereto. Methods for introducing apolynucleotide construct into animal cells are known in the art andincluding as non limiting examples stable transformation methods whereinthe polynucleotide construct is integrated into the genome of the cell,transient transformation methods wherein the polynucleotide construct isnot integrated into the genome of the cell and virus mediated methods.Said polynucleotides may be introduced into a cell by for example,recombinant viral vectors (e.g. retroviruses, adenoviruses), liposomeand the like. For example, transient transformation methods include forexample microinjection, electroporation or particle bombardment. Saidpolynucleotides may be included in vectors, more particularly plasmidsor virus, in view of being expressed in cells.

Electroporation

A more preferred embodiment of the invention, polynucleotides encodingpolypeptides according to the present invention can be mRNA which isintroduced directly into the cells, for example by electroporation. Theinventors determined the optimal condition for mRNA electroporation inT-cell.

The inventor used the cytoPulse technology which allows, by the use ofpulsed electric fields, to transiently permeabilize living cells fordelivery of material into the cells. The technology, based on the use ofPulseAgile (Cellectis property) electroporation waveforms grants theprecise control of pulse duration, intensity as well as the intervalbetween pulses (U.S. Pat. No. 6,010,613 and International PCTapplication WO2004083379). All these parameters can be modified in orderto reach the best conditions for high transfection efficiency withminimal mortality. Basically, the first high electric field pulses allowpore formation, while subsequent lower electric field pulses allow tomove the polynucleotide into the cell. In one aspect of the presentinvention, the inventor describe the steps that led to achievementof >95% transfection efficiency of mRNA in T cells, and the use of theelectroporation protocol to transiently express different kind ofproteins in T cells. In particular the invention relates to a method oftransforming T cell comprising contacting said T cell with RNA andapplying to T cell an agile pulse sequence consisting of:

-   -   (a) one electrical pulse with a voltage range from 2250 to 3000        V per centimeter, a pulse width of 0.1 ms and a pulse interval        of 0.2 to 10 ms between the electrical pulses of step (a) and        (b);    -   (b) one electrical pulse with a voltage range from 2250 to 3000        V with a pulse width of 100 ms and a pulse interval of 100 ms        between the electrical pulse of step (b) and the first        electrical pulse of step (c); and    -   (c) 4 electrical pulses with a voltage of 325 V with a pulse        width of 0.2 ms and a pulse interval of 2 ms between each of 4        electrical pulses.

In particular embodiment, the method of transforming T cell comprisingcontacting said T cell with RNA and applying to T cell an agile pulsesequence consisting of:

-   -   (a) one electrical pulse with a voltage of 2250, 2300, 2350,        2400, 2450, 2500, 2550, 2400, 2450, 2500, 2600, 2700, 2800, 2900        or 3000V per centimeter, a pulse width of 0.1 ms and a pulse        interval of 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 ms between        the electrical pulses of step (a) and (b);    -   (b) one electrical pulse with a voltage range from 2250, of        2250, 2300, 2350, 2400, 2450, 2500, 2550, 2400, 2450, 2500,        2600, 2700, 2800, 2900 or 3000V with a pulse width of 100 ms and        a pulse interval of 100 ms between the electrical pulse of        step (b) and the first electrical pulse of step (c); and    -   (c) 4 electrical pulses with a voltage of 325 V with a pulse        width of 0.2 ms and a pulse interval of 2 ms between each of 4        electrical pulses.

Any values included in the value range described above are disclosed inthe present application. Electroporation medium can be any suitablemedium known in the art. Preferably, the electroporation medium hasconductivity in a range spanning 0.01 to 1.0 milliSiemens.

In particular embodiments, as non limiting examples, said RNA encodes arare-cutting endonuclase, one monomer of the rare-cutting endonucleasesuch as Half-TALE-nuclease, a Chimeric Antigen Receptor, at least onecomponent of the multi-chain chimeric antigen receptor, a pTalpha orfunctional variant thereof, an exogenous nucleic acid, one additionalcatalytic domain.

Activation and Expansion of T Cells

Whether prior to or after genetic modification of the T cells, the Tcells can be activated and expanded generally using methods asdescribed, for example, in U.S. Pat. Nos. 6,352,694; 6,534,055;6,905,680; 6,692,964; 5,858,358; 6,887,466; 6,905,681; 7,144,575;7,067,318; 7,172,869; 7,232,566; 7,175,843; 5,883,223; 6,905,874;6,797,514; 6,867,041; and U.S. Patent Application Publication No.20060121005. T cells can be expanded in vitro or in vivo.

Generally, the T cells of the invention are expanded by contact with asurface having attached thereto an agent that stimulates a CD3 TCRcomplex associated signal and a ligand that stimulates a co-stimulatorymolecule on the surface of the T cells.

In particular, T cell populations may be stimulated in vitro such as bycontact with an anti-CD3 antibody, or antigen-binding fragment thereof,or an anti-CD2 antibody immobilized on a surface, or by contact with aprotein kinase C activator (e.g., bryostatin) in conjunction with acalcium ionophore. For co-stimulation of an accessory molecule on thesurface of the T cells, a ligand that binds the accessory molecule isused. For example, a population of T cells can be contacted with ananti-CD3 antibody and an anti-CD28 antibody, under conditionsappropriate for stimulating proliferation of the T cells. To stimulateproliferation of either CD4+ T cells or CD8+ T cells, an anti-CD3antibody and an anti-CD28 antibody. For example, the agents providingeach signal may be in solution or coupled to a surface. As those ofordinary skill in the art can readily appreciate, the ratio of particlesto cells may depend on particle size relative to the target cell. Infurther embodiments of the present invention, the cells, such as Tcells, are combined with agent-coated beads, the beads and the cells aresubsequently separated, and then the cells are cultured. In analternative embodiment, prior to culture, the agent-coated beads andcells are not separated but are cultured together. Cell surface proteinsmay be ligated by allowing paramagnetic beads to which anti-CD3 andanti-CD28 are attached (3×28 beads) to contact the T cells. In oneembodiment the cells (for example, 4 to 10 T cells) and beads (forexample, DYNABEADS® M-450 CD3/CD28 T paramagnetic beads at a ratio of1:1) are combined in a buffer, preferably PBS (without divalent cationssuch as, calcium and magnesium). Again, those of ordinary skill in theart can readily appreciate any cell concentration may be used. Themixture may be cultured for several hours (about 3 hours) to about 14days or any hourly integer value in between. In another embodiment, themixture may be cultured for 21 days. Conditions appropriate for T cellculture include an appropriate media (e.g., Minimal Essential Media orRPMI Media 1640 or, X-vivo 5, (Lonza)) that may contain factorsnecessary for proliferation and viability, including serum (e.g., fetalbovine or human serum), interleukin-2 (IL-2), insulin, IFN-g, 1L-4,1L-7, GM-CSF, -10, -2, 1L-15, TGFp, and TNF- or any other additives forthe growth of cells known to the skilled artisan. Other additives forthe growth of cells include, but are not limited to, surfactant,plasmanate, and reducing agents such as N-acetyl-cysteine and2-mercaptoethanoi. Media can include RPMI 1640, A1M-V, DMEM, MEM, a-MEM,F-12, X-Vivo 1, and X-Vivo 20, Optimizer, with added amino acids, sodiumpyruvate, and vitamins, either serum-free or supplemented with anappropriate amount of serum (or plasma) or a defined set of hormones,and/or an amount of cytokine(s) sufficient for the growth and expansionof T cells. Antibiotics, e.g., penicillin and streptomycin, are includedonly in experimental cultures, not in cultures of cells that are to beinfused into a subject. The target cells are maintained under conditionsnecessary to support growth, for example, an appropriate temperature(e.g., 37° C.) and atmosphere (e.g., air plus 5% C02). T cells that havebeen exposed to varied stimulation times may exhibit differentcharacteristics

In another particular embodiment, said cells can be expanded byco-culturing with tissue or cells. Said cells can also be expanded invivo, for example in the subject's blood after administrating said cellinto the subject.

Modified T-Cells

In the scope of the present invention is also encompassed an isolated Tcell obtained according to any one of the methods previously described.Said T-cell according to the present invention can be derived from astem cell. The stem cells can be adult stem cells, embryonic stem cells,more particularly non-human stem cells, cord blood stem cells,progenitor cells, bone marrow stem cells, induced pluripotent stemcells, totipotent stem cells or hematopoietic stem cells. Representativehuman cells are CD34+ cells. Said isolated cell can also be a dendriticcell, a NK-cell, a B-cell or a T-cell selected from the group consistingof inflammatory T-lymphocytes, cytotoxic T-lymphocytes, regulatoryT-lymphocytes or helper T-lymphocytes. In another embodiment, said cellcan be derived from the group consisting of CD4+ T-lymphocytes and CD8+T-lymphocytes. Prior to expansion and genetic modification of the cellsof the invention, a source of cells can be obtained from a subjectthrough a variety of non-limiting methods. T cells can be obtained froma number of non-limiting sources, including peripheral blood mononuclearcells, bone marrow, lymph node tissue, cord blood, thymus tissue, tissuefrom a site of infection, ascites, pleural effusion, spleen tissue, andtumors. In certain embodiments of the present invention, any number of Tcell lines available and known to those skilled in the art, may be used.In another embodiment, said cell can be derived from a healthy donor,from a patient diagnosed with cancer or from a patient diagnosed with aninfection. In another embodiment, said cell is part of a mixedpopulation of cells which present different phenotypic characteristics.In the scope of the present invention is also encompassed a cell lineobtained from a transformed T-cell according to the method previouslydescribed. Modified cells resistant to an immunosuppressive treatmentand susceptible to be obtained by the previous method are encompassed inthe scope of the present invention.

In another embodiment, said isolated cell according to the presentinvention comprises one inactivated gene selected from the groupconsisting of CD52, GR, TCR alpha and TCR beta and/or expresses a CAR, amulti-chain CAR and/or a pTalpha transgene. In another embodiment, saidisolated cell according to the present invention comprises twoinactivated genes selected from the group consisting of CD52 and GR,CD52 and TCR alpha, CDR52 and TCR beta, GR and TCR alpha, GR and TCRbeta, TCR alpha and TCR beta and/or expresses a CAR, a multi-chain CARand/or a pTalpha transgene.

In another embodiment, TCR is rendered not functional in the cellsaccording to the invention by inactivating TCR alpha gene and/or TCRbeta gene(s). The above strategies are used more particularly to avoidGvHD. In a particular aspect of the present invention is a method toobtain modified cells derived from an individual, wherein said cells canproliferate independently of the Major Histocompatibility Complexsignaling pathway. Said method comprises the following steps:

-   -   (a) Recovering cells from said individual;    -   (b) Genetically modifying said cells ex-vivo by inactivating TCR        alpha or TCR beta genes;    -   (c) Cultivating genetically modified T-cells in vitro in        appropriate conditions to amplify said cells.

Modified cells, which can proliferate independently of the MajorHistocompatibility Complex signaling pathway, susceptible to be obtainedby this method are encompassed in the scope of the present invention.Said modified cells can be used in a particular aspect of the inventionfor treating patients in need thereof against Host versus Graft (HvG)rejection and Graft versus Host Disease (GvHD); therefore in the scopeof the present invention is a method of treating patients in needthereof against Host versus Graft (HvG) rejection and Graft versus HostDisease (GvHD) comprising treating said patient by administering to saidpatient an effective amount of modified cells comprising inactivated TCRalpha and/or TCR beta genes.

Therapeutic Applications

In another embodiment, isolated cell obtained by the different methodsor cell line derived from said isolated cell as previously described canbe used as a medicament. In another embodiment, said medicament can beused for treating cancer or infections in a patient in need thereof. Inanother embodiment, said isolated cell according to the invention orcell line derived from said isolated cell can be used in the manufactureof a medicament for treatment of a cancer or a viral infection in apatient in need thereof.

In another aspect, the present invention relies on methods for treatingpatients in need thereof, said method comprising at least one of thefollowing steps:

-   -   (a) providing a T-cell obtainable by any one of the methods        previously described;    -   (b) Administrating said transformed T-cells to said patient,

On one embodiment, said T cells of the invention can undergo robust invivo T cell expansion and can persist for an extended amount of time.

Said treatment can be ameliorating, curative or prophylactic. It may beeither part of an autologous immunotherapy or part of an allogenicimmunotherapy treatment. By autologous, it is meant that cells, cellline or population of cells used for treating patients are originatingfrom said patient or from a Human Leucocyte Antigen (HLA) compatibledonor. By allogeneic is meant that the cells or population of cells usedfor treating patients are not originating from said patient but from adonor.

The invention is particularly suited for allogenic immunotherapy,insofar as it enables the transformation of T-cells, typically obtainedfrom donors, into non-alloreactive cells. This may be done understandard protocols and reproduced as many times as needed. The resultedmodified T cells may be pooled and administrated to one or severalpatients, being made available as an “off the shelf” therapeuticproduct.

Cells that can be used with the disclosed methods are described in theprevious section. Said treatment can be used to treat patients diagnosedwith cancer, viral infection, autoimmune disorders or Graft versus HostDisease (GvHD). Cancers that may be treated include tumors that are notvascularized, or not yet substantially vascularized, as well asvascularized tumors. The cancers may comprise nonsolid tumors (such ashematological tumors, for example, leukemias and lymphomas) or maycomprise solid tumors. Types of cancers to be treated with the CARs ofthe invention include, but are not limited to, carcinoma, blastoma, andsarcoma, and certain leukemia or lymphoid malignancies, benign andmalignant tumors, and malignancies e.g., sarcomas, carcinomas, andmelanomas. Adult tumors/cancers and pediatric tumors/cancers are alsoincluded.

It can be a treatment in combination with one or more therapies againstcancer selected from the group of antibodies therapy, chemotherapy,cytokines therapy, dendritic cell therapy, gene therapy, hormonetherapy, laser light therapy and radiation therapy.

According to a preferred embodiment of the invention, said treatment canbe administrated into patients undergoing an immunosuppressivetreatment. Indeed, the present invention preferably relies on cells orpopulation of cells, which have been made resistant to at least oneimmunosuppressive agent due to the inactivation of a gene encoding areceptor for such immunosuppressive agent. In this aspect, theimmunosuppressive treatment should help the selection and expansion ofthe T-cells according to the invention within the patient.

The administration of the cells or population of cells according to thepresent invention may be carried out in any convenient manner, includingby aerosol inhalation, injection, ingestion, transfusion, implantationor transplantation. The compositions described herein may beadministered to a patient subcutaneously, intradermaliy, intratumorally,intranodally, intramedullary, intramuscularly, by intravenous orintralymphatic injection, or intraperitoneally. In one embodiment, thecell compositions of the present invention are preferably administeredby intravenous injection.

The administration of the cells or population of cells can consist ofthe administration of 10⁴-10⁹ cells per kg body weight, preferably 10⁵to 10⁶ cells/kg body weight including all integer values of cell numberswithin those ranges. The cells or population of cells can beadministrated in one or more doses. In another embodiment, saideffective amount of cells are administrated as a single dose. In anotherembodiment, said effective amount of cells are administrated as morethan one dose over a period time. Timing of administration is within thejudgment of managing physician and depends on the clinical condition ofthe patient. The cells or population of cells may be obtained from anysource, such as a blood bank or a donor. While individual needs vary,determination of optimal ranges of effective amounts of a given celltype for a particular disease or conditions within the skill of the art.An effective amount means an amount which provides a therapeutic orprophylactic benefit. The dosage administrated will be dependent uponthe age, health and weight of the recipient, kind of concurrenttreatment, if any, frequency of treatment and the nature of the effectdesired.

In another embodiment, said effective amount of cells or compositioncomprising those cells are administrated parenterally. Saidadministration can be an intravenous administration. Said administrationcan be directly done by injection within a tumor.

In certain embodiments of the present invention, cells are administeredto a patient in conjunction with (e.g., before, simultaneously orfollowing) any number of relevant treatment modalities, including butnot limited to treatment with agents such as antiviral therapy,cidofovir and interleukin-2, Cytarabine (also known as ARA-C) ornataliziimab treatment for MS patients or efaliztimab treatment forpsoriasis patients or other treatments for PML patients. In furtherembodiments, the T cells of the invention may be used in combinationwith chemotherapy, radiation, immunosuppressive agents, such ascyclosporin, azathioprine, methotrexate, mycophenolate, and FK506,antibodies, or other immunoablative agents such as CAM PATH, anti-CD3antibodies or other antibody therapies, cytoxin, fludaribine,cyclosporin, FK506, rapamycin, mycoplienolic acid, steroids, FR901228,cytokines, and irradiation. These drugs inhibit either the calciumdependent phosphatase calcineurin (cyclosporine and FK506) or inhibitthe p70S6 kinase that is important for growth factor induced signaling(rapamycin) (Liu et al., Cell 66:807-815, 11; Henderson et al., Immun.73:316-321, 1991; Bierer et al., Citrr. Opin. mm n. 5:763-773, 93). In afurther embodiment, the cell compositions of the present invention areadministered to a patient in conjunction with (e.g., before,simultaneously or following) bone marrow transplantation, T cellablative therapy using either chemotherapy agents such as, fludarabine,external-beam radiation therapy (XRT), cyclophosphamide, or antibodiessuch as OKT3 or CAMPATH, In another embodiment, the cell compositions ofthe present invention are administered following B-cell ablative therapysuch as agents that react with CD20, e.g., Rituxan. For example, in oneembodiment, subjects may undergo standard treatment with high dosechemotherapy followed by peripheral blood stem cell transplantation. Incertain embodiments, following the transplant, subjects receive aninfusion of the expanded immune cells of the present invention. In anadditional embodiment, expanded cells are administered before orfollowing surgery. Said modified cells obtained by any one of themethods described here can be used in a particular aspect of theinvention for treating patients in need thereof against Host versusGraft (HvG) rejection and Graft versus Host Disease (GvHD); therefore inthe scope of the present invention is a method of treating patients inneed thereof against Host versus Graft (HvG) rejection and Graft versusHost Disease (GvHD) comprising treating said patient by administering tosaid patient an effective amount of modified cells comprisinginactivated TCR alpha and/or TCR beta genes.

Example of Method to Engineer Human Allogeneic Cells for Immunotherapy

For a better understanding of the invention, one example of method toengineer human allogenic cells for immunotherapy is illustrated in FIG.5. The method comprising a combination of one or several of thefollowing steps:

-   1. Providing T-cells from a cell culture or from a blood sample from    one individual patient or from blood bank and activating said T    cells using anti-CD3/C28 activator beads. The beads provide both the    primary and co-stimulatory signals that are required for activation    and expansion of T cells.-   2. a) Transducing said cells with pTalpha or functional variant    thereof transgene to support CD3 surface expression and allow cell    expansion through stimulation of CD3 complex. TCR disruption is    expected to the elimination of the TCR complex and removes    alloreactivity (GvHD) but may alter allogenic cells expansion due to    the loss of CD3 signaling component. Transduced cells are expected    to express pTalpha chain or functional variant thereof. This pTalpha    chain pairs with TCRbeta chain and CD3 signaling components to form    the preTCR complex and, thus restore a functional CD3 complex and    support activation or stimulation of inactivated TCRalpha cells.    Transduction of T-cells with pTalpha lentiviral vector can be    realized before or after TCRalpha inactivation.    -   b) Transducing said cells with multi-chain CARs allow        redirecting T cells against antigens expressed at the surface of        target cells from various malignancies including lymphomas and        solid tumors. To improve the function of co-stimulatory domain,        the inventors have designed a multi-chain CAR derived from FcεRI        as previously described. Transduction can be realized before or        after the inactivation of TCRalpha and CD52 genes.-   3. Engineering non alloreactive and immunosuppressive resistant T    cells:    -   a) It is possible to Inactivate TCR alpha in said cells to        eliminate the TCR from the surface of the cell and prevent        recognition of host tissue as foreign by TCR of allogenic and        thus to avoid GvHD.    -   b) It is also possible to inactive one gene encoding target for        immunosuppressive agent to render said cells resistant to        immunosuppressive treatment to prevent graft rejection without        affecting transplanted T cells. In this example, target of        immunosuppressive agents is CD52 and immunosuppressive agent is        a humanized monoclonal anti-CD52 antibody.    -    It has been shown by the inventors that the use of        TALE-nuclease by allowing higher rates of DSB events within        T-cells was particularly advantageous to achieve the above        double inactivation in T-cells. Preferably, TCRalpha and CD52        genes are inactivated by electoporating T cells with mRNA coding        for TALE-nuclease targeting said genes. It has been found by the        inventors that using mRNA resulted into high transformation rate        was less harmful to T-cells and so, was critical in the process        of engineering T-cells. Then, inactivated T cells are sorted        using magnetic beads. For example, T cells expressing CD52 are        removed by fixation on a solid surface, and inactivated cells        are not exposed of the stress of being passed through a column.        This gentle method increases the concentration of properly        engineered T-cells.-   4. Expansion in vitro of engineered T-cells prior to administration    to a patient or in vivo following administration to a patient    through stimulation of CD3 complex. Before administration step,    patients are subjected to an immunosuppressive treatment such as    CAMPATH1-H, a humanized monoclonal antibody anti-CD52.-   5. Optionally exposed said cells with bispecific antibodies ex vivo    prior to administration to a patient or in vivo following    administration to a patient to bring the engineered cells into    proximity to a target antigen.

OTHER DEFINITIONS

-   -   Amino acid residues in a polypeptide sequence are designated        herein according to the one-letter code, in which, for example,        Q means Gln or Glutamine residue, R means Arg or Arginine        residue and D means Asp or Aspartic acid residue.    -   Amino acid substitution means the replacement of one amino acid        residue with another, for instance the replacement of an        Arginine residue with a Glutamine residue in a peptide sequence        is an amino acid substitution.    -   Nucleotides are designated as follows: one-letter code is used        for designating the base of a nucleoside: a is adenine, t is        thymine, c is cytosine, and g is guanine. For the degenerated        nucleotides, r represents g or a (purine nucleotides), k        represents g or t, s represents g or c, w represents a or t, m        represents a or c, y represents t or c (pyrimidine nucleotides),        d represents g, a or t, v represents g, a or c, b represents g,        t or c, h represents a, t or c, and n represents g, a, t or c.    -   “As used herein, “nucleic acid” or “polynucleotides” refers to        nucleotides and/or polynucleotides, such as deoxyribonucleic        acid (DNA) or ribonucleic acid (RNA), oligonucleotides,        fragments generated by the polymerase chain reaction (PCR), and        fragments generated by any of ligation, scission, endonuclease        action, and exonuclease action. Nucleic acid molecules can be        composed of monomers that are naturally-occurring nucleotides        (such as DNA and RNA), or analogs of naturally-occurring        nucleotides (e.g., enantiomeric forms of naturally-occurring        nucleotides), or a combination of both. Modified nucleotides can        have alterations in sugar moieties and/or in pyrimidine or        purine base moieties. Sugar modifications include, for example,        replacement of one or more hydroxyl groups with halogens, alkyl        groups, amines, and azido groups, or sugars can be        functionalized as ethers or esters. Moreover, the entire sugar        moiety can be replaced with sterically and electronically        similar structures, such as aza-sugars and carbocyclic sugar        analogs. Examples of modifications in a base moiety include        alkylated purines and pyrimidines, acylated purines or        pyrimidines, or other well-known heterocyclic substitutes.        Nucleic acid monomers can be linked by phosphodiester bonds or        analogs of such linkages. Nucleic acids can be either single        stranded or double stranded.    -   by “polynucleotide successively comprising a first region of        homology to sequences upstream of said double-stranded break, a        sequence to be inserted in the genome of said cell and a second        region of homology to sequences downstream of said        double-stranded break” it is intended to mean a DNA construct or        a matrix comprising a first and second portion that are        homologous to regions 5′ and 3′ of a DNA target in situ. The DNA        construct also comprises a third portion positioned between the        first and second portion which comprise some homology with the        corresponding DNA sequence in situ or alternatively comprise no        homology with the regions 5′ and 3′ of the DNA target in situ.        Following cleavage of the DNA target, a homologous recombination        event is stimulated between the genome containing the targeted        gene comprised in the locus of interest and this matrix, wherein        the genomic sequence containing the DNA target is replaced by        the third portion of the matrix and a variable part of the first        and second portions of said matrix.    -   by “DNA target”, “DNA target sequence”, “target DNA sequence”,        “nucleic acid target sequence”, “target sequence”, or        “processing site” is intended a polynucleotide sequence that can        be targeted and processed by a rare-cutting endonuclease        according to the present invention. These terms refer to a        specific DNA location, preferably a genomic location in a cell,        but also a portion of genetic material that can exist        independently to the main body of genetic material such as        plasmids, episomes, virus, transposons or in organelles such as        mitochondria as non-limiting example. As non-limiting examples        of TALE-nuclease targets, targeted genomic sequences generally        consist of two 17-bp long sequences (called half targets)        separated by a 15-bp spacer. Each half-target is recognized by        repeats of TALE-nucleases listed in tables 1, 5, 6 and 10 as        non-limiting examples, encoded in plasmids, under the control of        EF1-alpha promoter or T7 promoter. The nucleic acid target        sequence is defined by the 5′ to 3′ sequence of one strand of        said target, as indicated in tables 1, 5, 6 and 10.    -   By chimeric antigen receptor (CAR) is intended molecules that        combine a binding domain against a component present on the        target cell, for example an antibody-based specificity for a        desired antigen (e.g., tumor antigen) with a T cell        receptor-activating intracellular domain to generate a chimeric        protein that exhibits a specific anti-target cellular immune        activity. Generally, CAR consists of an extracellular single        chain antibody (scFvFc) fused to the intracellular signaling        domain of the T cell antigen receptor complex zeta chain        (scFvFc:ζ) and have the ability, when expressed in T cells, to        redirect antigen recognition based on the monoclonal antibody's        specificity. One example of CAR used in the present invention is        a CAR directing against CD19 antigen and can comprise as non        limiting example the amino acid sequence: SEQ ID NO: 73    -   By “delivery vector” or “delivery vectors” is intended any        delivery vector which can be used in the present invention to        put into cell contact (i.e “contacting”) or deliver inside cells        or subcellular compartments (i.e “introducing”) agents/chemicals        and molecules (proteins or nucleic acids) needed in the present        invention. It includes, but is not limited to liposomal delivery        vectors, viral delivery vectors, drug delivery vectors, chemical        carriers, polymeric carriers, lipoplexes, polyplexes,        dendrimers, microbubbles (ultrasound contrast agents),        nanoparticles, emulsions or other appropriate transfer vectors.        These delivery vectors allow delivery of molecules, chemicals,        macromolecules (genes, proteins), or other vectors such as        plasmids, peptides developed by Diatos. In these cases, delivery        vectors are molecule carriers. By “delivery vector” or “delivery        vectors” is also intended delivery methods to perform        transfection.    -   The terms “vector” or “vectors” refer to a nucleic acid molecule        capable of transporting another nucleic acid to which it has        been linked. A “vector” in the present invention includes, but        is not limited to, a viral vector, a plasmid, a RNA vector or a        linear or circular DNA or RNA molecule which may consists of a        chromosomal, non chromosomal, semi-synthetic or synthetic        nucleic acids. Preferred vectors are those capable of autonomous        replication (episomal vector) and/or expression of nucleic acids        to which they are linked (expression vectors). Large numbers of        suitable vectors are known to those of skill in the art and        commercially available.

Viral vectors include retrovirus, adenovirus, parvovirus (e. g.adenoassociated viruses), coronavirus, negative strand RNA viruses suchas orthomyxovirus (e. g., influenza virus), rhabdovirus (e. g., rabiesand vesicular stomatitis virus), paramyxovirus (e. g. measles andSendai), positive strand RNA viruses such as picornavirus andalphavirus, and double-stranded DNA viruses including adenovirus,herpesvirus (e. g., Herpes Simplex virus types 1 and 2, Epstein-Barrvirus, cytomegalovirus), and poxvirus (e. g., vaccinia, fowlpox andcanarypox). Other viruses include Norwalk virus, togavirus, flavivirus,reoviruses, papovavirus, hepadnavirus, and hepatitis virus, for example.Examples of retroviruses include: avian leukosis-sarcoma, mammalianC-type, B-type viruses, D type viruses, HTLV-BLV group, lentivirus,spumavirus (Coffin, J. M., Retroviridae: The viruses and theirreplication, In Fundamental Virology, Third Edition, B. N. Fields, etal., Eds., Lippincott-Raven Publishers, Philadelphia, 1996).

-   -   By “lentiviral vector” is meant HIV-Based lentiviral vectors        that are very promising for gene delivery because of their        relatively large packaging capacity, reduced immunogenicity and        their ability to stably transduce with high efficiency a large        range of different cell types. Lentiviral vectors are usually        generated following transient transfection of three (packaging,        envelope and transfer) or more plasmids into producer cells.        Like HIV, lentiviral vectors enter the target cell through the        interaction of viral surface glycoproteins with receptors on the        cell surface. On entry, the viral RNA undergoes reverse        transcription, which is mediated by the viral reverse        transcriptase complex. The product of reverse transcription is a        double-stranded linear viral DNA, which is the substrate for        viral integration in the DNA of infected cells. By “integrative        lentiviral vectors (or LV)”, is meant such vectors as non        limiting example, that are able to integrate the genome of a        target cell. At the opposite by “non integrative lentiviral        vectors (or NILV)” is meant efficient gene delivery vectors that        do not integrate the genome of a target cell through the action        of the virus integrase.    -   Delivery vectors and vectors can be associated or combined with        any cellular permeabilization techniques such as sonoporation or        electroporation or derivatives of these techniques.    -   By cell or cells is intended any eukaryotic living cells,        primary cells and cell lines derived from these organisms for in        vitro cultures.    -   By “primary cell” or “primary cells” are intended cells taken        directly from living tissue (i.e. biopsy material) and        established for growth in vitro, that have undergone very few        population doublings and are therefore more representative of        the main functional components and characteristics of tissues        from which they are derived from, in comparison to continuous        tumorigenic or artificially immortalized cell lines.

As non limiting examples cell lines can be selected from the groupconsisting of CHO-K1 cells; HEK293 cells; Caco2 cells; U2-OS cells; NIH3T3 cells; NSO cells; SP2 cells; CHO-S cells; DG44 cells; K-562 cells,U-937 cells; MRC5 cells; IMR90 cells; Jurkat cells; HepG2 cells; HeLacells; HT-1080 cells; HCT-116 cells; Hu-h7 cells; Huvec cells; Molt 4cells.

All these cell lines can be modified by the method of the presentinvention to provide cell line models to produce, express, quantify,detect, study a gene or a protein of interest; these models can also beused to screen biologically active molecules of interest in research andproduction and various fields such as chemical, biofuels, therapeuticsand agronomy as non-limiting examples.

-   -   by “mutation” is intended the substitution, deletion, insertion        of up to one, two, three, four, five, six, seven, eight, nine,        ten, eleven, twelve, thirteen, fourteen, fifteen, twenty, twenty        five, thirty, forty, fifty, or more nucleotides/amino acids in a        polynucleotide (cDNA, gene) or a polypeptide sequence. The        mutation can affect the coding sequence of a gene or its        regulatory sequence. It may also affect the structure of the        genomic sequence or the structure/stability of the encoded mRNA.    -   by “variant(s)”, it is intended a repeat variant, a variant, a        DNA binding variant, a TALE-nuclease variant, a polypeptide        variant obtained by mutation or replacement of at least one        residue in the amino acid sequence of the parent molecule.    -   by “functional variant” is intended a catalytically active        mutant of a protein or a protein domain; such mutant may have        the same activity compared to its parent protein or protein        domain or additional properties, or higher or lower activity.    -   By “gene” is meant the basic unit of heredity, consisting of a        segment of DNA arranged in a linear manner along a chromosome,        which codes for a specific protein or segment of protein. A gene        typically includes a promoter, a 5′ untranslated region, one or        more coding sequences (exons), optionally introns, a 3′        untranslated region. The gene may further comprise a terminator,        enhancers and/or silencers.    -   As used herein, the term “locus” is the specific physical        location of a DNA sequence (e.g. of a gene) on a chromosome. The        term “locus” can refer to the specific physical location of a        rare-cutting endonuclease target sequence on a chromosome. Such        a locus can comprise a target sequence that is recognized and/or        cleaved by a rare-cutting endonuclease according to the        invention. It is understood that the locus of interest of the        present invention can not only qualify a nucleic acid sequence        that exists in the main body of genetic material (i.e. in a        chromosome) of a cell but also a portion of genetic material        that can exist independently to said main body of genetic        material such as plasmids, episomes, virus, transposons or in        organelles such as mitochondria as non-limiting examples.    -   The term “endonuclease” refers to any wild-type or variant        enzyme capable of catalyzing the hydrolysis (cleavage) of bonds        between nucleic acids within a DNA or RNA molecule, preferably a        DNA molecule. Endonucleases do not cleave the DNA or RNA        molecule irrespective of its sequence, but recognize and cleave        the DNA or RNA molecule at specific polynucleotide sequences,        further referred to as “target sequences” or “target sites”.        Endonucleases can be classified as rare-cutting endonucleases        when having typically a polynucleotide recognition site greater        than 12 base pairs (bp) in length, more preferably of 14-55 bp.        Rare-cutting endonucleases significantly increase HR by inducing        DNA double-strand breaks (DSBs) at a defined locus (Rouet, Smih        et al. 1994; Choulika, Perrin et al. 1995; Pingoud and Silva        2007). Rare-cutting endonucleases can for example be a homing        endonuclease (Paques and Duchateau 2007), a chimeric Zinc-Finger        nuclease (ZFN) resulting from the fusion of engineered        zinc-finger domains with the catalytic domain of a restriction        enzyme such as FokI (Porteus and Carroll 2005) or a chemical        endonuclease (Eisenschmidt, Lanio et al. 2005; Arimondo, Thomas        et al. 2006). In chemical endonucleases, a chemical or peptidic        cleaver is conjugated either to a polymer of nucleic acids or to        another DNA recognizing a specific target sequence, thereby        targeting the cleavage activity to a specific sequence. Chemical        endonucleases also encompass synthetic nucleases like conjugates        of orthophenanthroline, a DNA cleaving molecule, and        triplex-forming oligonucleotides (TFOs), known to bind specific        DNA sequences (Kalish and Glazer 2005). Such chemical        endonucleases are comprised in the term “endonuclease” according        to the present invention.

Rare-cutting endonucleases can also be for example TALE-nucleases, a newclass of chimeric nucleases using a FokI catalytic domain and a DNAbinding domain derived from Transcription Activator Like Effector(TALE), a family of proteins used in the infection process by plantpathogens of the Xanthomonas genus (Boch, Scholze et al. 2009; Moscouand Bogdanove 2009; Christian, Cermak et al. 2010; Li, Huang et al.).The functional layout of a FokI-based TALE-nuclease (TALE-nuclease) isessentially that of a ZFN, with the Zinc-finger DNA binding domain beingreplaced by the TALE domain. As such, DNA cleavage by a TALE-nucleaserequires two DNA recognition regions flanking an unspecific centralregion. Rare-cutting endonucleases encompassed in the present inventioncan also be derived from TALE-nucleases.

Rare-cutting endonuclease can be a homing endonuclease, also known underthe name of meganuclease. Such homing endonucleases are well-known tothe art (Stoddard 2005). Homing endonucleases recognize a DNA targetsequence and generate a single- or double-strand break. Homingendonucleases are highly specific, recognizing DNA target sites rangingfrom 12 to 45 base pairs (bp) in length, usually ranging from 14 to 40bp in length. The homing endonuclease according to the invention may forexample correspond to a LAGLIDADG endonuclease, to a HNH endonuclease,or to a GIY-YIG endonuclease. Preferred homing endonuclease according tothe present invention can be an I-CreI variant.

-   -   By a “TALE-nuclease” (TALEN) is intended a fusion protein        consisting of a nucleic acid-binding domain typically derived        from a Transcription Activator Like Effector (TALE) and one        nuclease catalytic domain to cleave a nucleic acid target        sequence. The catalytic domain is preferably a nuclease domain        and more preferably a domain having endonuclease activity, like        for instance I-TevI, ColE7, NucA and Fok-I. In a particular        embodiment, the TALE domain can be fused to a meganuclease like        for instance I-CreI and I-OnuI or functional variant thereof. In        a more preferred embodiment, said nuclease is a monomeric        TALE-Nuclease. A monomeric TALE-Nuclease is a TALE-Nuclease that        does not require dimerization for specific recognition and        cleavage, such as the fusions of engineered TAL repeats with the        catalytic domain of I-TevI described in WO2012138927.        Transcription Activator like Effector (TALE) are proteins from        the bacterial species Xanthomonas comprise a plurality of        repeated sequences, each repeat comprising di-residues in        position 12 and 13 (RVD) that are specific to each nucleotide        base of the nucleic acid targeted sequence. Binding domains with        similar modular base-per-base nucleic acid binding properties        (MBBBD) can also be derived from new modular proteins recently        discovered by the applicant in a different bacterial species.        The new modular proteins have the advantage of displaying more        sequence variability than TAL repeats. Preferably, RVDs        associated with recognition of the different nucleotides are HD        for recognizing C, NG for recognizing T, NI for recognizing A,        NN for recognizing G or A, NS for recognizing A, C, G or T, HG        for recognizing T, IG for recognizing T, NK for recognizing G,        HA for recognizing C, ND for recognizing C, HI for recognizing        C, HN for recognizing G, NA for recognizing G, SN for        recognizing G or A and YG for recognizing T, TL for recognizing        A, VT for recognizing A or G and SW for recognizing A. In        another embodiment, critical amino acids 12 and 13 can be        mutated towards other amino acid residues in order to modulate        their specificity towards nucleotides A, T, C and G and in        particular to enhance this specificity. TALE-nuclease have been        already described and used to stimulate gene targeting and gene        modifications (Boch, Scholze et al. 2009; Moscou and Bogdanove        2009; Christian, Cermak et al. 2010; Li, Huang et al.).        Engineered TAL-nucleases are commercially available under the        trade name TALEN™ (Cellectis, 8 rue de la Croix Jarry, 75013        Paris, France).    -   The term “cleavage” refers to the breakage of the covalent        backbone of a polynucleotide. Cleavage can be initiated by a        variety of methods including, but not limited to, enzymatic or        chemical hydrolysis of a phosphodiester bond. Both        single-stranded cleavage and double-stranded cleavage are        possible, and double-stranded cleavage can occur as a result of        two distinct single-stranded cleavage events. Double stranded        DNA, RNA, or DNA/RNA hybrid cleavage can result in the        production of either blunt ends or staggered ends.    -   By “fusion protein” is intended the result of a well-known        process in the art consisting in the joining of two or more        genes which originally encode for separate proteins or part of        them, the translation of said “fusion gene” resulting in a        single polypeptide with functional properties derived from each        of the original proteins.    -   “identity” refers to sequence identity between two nucleic acid        molecules or polypeptides. Identity can be determined by        comparing a position in each sequence which may be aligned for        purposes of comparison. When a position in the compared sequence        is occupied by the same base, then the molecules are identical        at that position. A degree of similarity or identity between        nucleic acid or amino acid sequences is a function of the number        of identical or matching nucleotides at positions shared by the        nucleic acid sequences. Various alignment algorithms and/or        programs may be used to calculate the identity between two        sequences, including FASTA, or BLAST which are available as a        part of the GCG sequence analysis package (University of        Wisconsin, Madison, Wis.), and can be used with, e.g., default        setting. For example, polypeptides having at least 70%, 85%,        90%, 95%, 98% or 99% identity to specific polypeptides described        herein and preferably exhibiting substantially the same        functions, as well as polynucleotide encoding such polypeptides,        are contemplated.    -   “similarity” describes the relationship between the amino acid        sequences of two or more polypeptides. BLASTP may also be used        to identify an amino acid sequence having at least 70%, 75%,        80%, 85%, 87.5%, 90%, 92.5%, 95%, 97.5%, 98%, 99% sequence        similarity to a reference amino acid sequence using a similarity        matrix such as BLOSUM45, BLOSUM62 or BLOSUM80. Unless otherwise        indicated a similarity score will be based on use of BLOSUM62.        When BLASTP is used, the percent similarity is based on the        BLASTP positives score and the percent sequence identity is        based on the BLASTP identities score. BLASTP “Identities” shows        the number and fraction of total residues in the high scoring        sequence pairs which are identical; and BLASTP “Positives” shows        the number and fraction of residues for which the alignment        scores have positive values and which are similar to each other        Amino acid sequences having these degrees of identity or        similarity or any intermediate degree of identity of similarity        to the amino acid sequences disclosed herein are contemplated        and encompassed by this disclosure. The polynucleotide sequences        of similar polypeptides are deduced using the genetic code and        may be obtained by conventional means. For example, a functional        variant of pTalpha can have 70%, 75%, 80%, 85%, 87.5%, 90%,        92.5%, 95%, 97.5%, 98%, 99% sequence similarity to the amino        acid sequence of SEQ ID NO: 107. A polynucleotide encoding such        a functional variant would be produced by reverse translating        its amino acid sequence using the genetic code.    -   “signal-transducing domain” or “co-stimulatory ligand” refers to        a molecule on an antigen presenting cell that specifically binds        a cognate co-stimulatory molecule on a T-cell, thereby providing        a signal which, in addition to the primary signal provided by,        for instance, binding of a TCR/CD3 complex with an MHC molecule        loaded with peptide, mediates a T cell response, including, but        not limited to, proliferation activation, differentiation and        the like. A co-stimulatory ligand can include but is not limited        to CD7, B7-1 (CD80), B7-2 (CD86), PD-L1, PD-L2, 4-1BBL, OX40L,        inducible costimulatory igand (ICOS-L), intercellular adhesion        molecule (ICAM, CD30L, CD40, CD70, CD83, HLA-G, MICA, M1CB,        HVEM, lymphotoxin beta receptor, 3/TR6, ILT3, ILT4, an agonist        or antibody that binds Toll ligand receptor and a ligand that        specifically binds with B7-H3. A co-stimulatory ligand also        encompasses, inter alia, an antibody that specifically binds        with a co-stimulatory molecule present on a T cell, such as but        not limited to, CD27, CD28, 4-IBB, OX40, CD30, CD40, PD-1, ICOS,        lymphocyte function-associated antigen-1 (LFA-1), CD2, CD7,        LTGHT, NKG2C, B7-H3, a ligand that specifically binds with CD83.

A “co-stimulatory molecule” refers to the cognate binding partner on aTcell that specifically binds with a co-stimulatory ligand, therebymediating a co-stimulatory response by the cell, such as, but notlimited to proliferation. Co-stimulatory molecules include, but are notlimited to an MHC class I molecule, BTLA and Toll ligand receptor.

A “co-stimulatory signal” as used herein refers to a signal, which incombination with primary signal, such as TCR/CD3 ligation, leads to Tcell proliferation and/or upregulation or downregulation of keymolecules.

-   -   “bispecific antibody” refers to an antibody that has binding        sites for two different antigens within a single antibody        molecule. It will be appreciated by those skilled in the art        that other molecules in addition to the canonical antibody        structure may be constructed with two binding specificities. It        will further be appreciated that antigen binding by bispecific        antibodies may be simultaneous or sequential. Bispecific        antibodies can be produced by chemical techniques (see e.g.,        Kranz et al. (1981) Proc. Natl. Acad. Sci. USA 78, 5807), by        “polydoma” techniques (See U.S. Pat. No. 4,474,893) or by        recombinant DNA techniques, which all are known per se. As a non        limiting example, each binding domain comprises at least one        variable region from an antibody heavy chain (“VH or H region”),        wherein the VH region of the first binding domain specifically        binds to the lymphocyte marker such as CD3, and the VH region of        the second binding domain specifically binds to tumor antigen.    -   The term “extracellular ligand-binding domain” as used herein is        defined as an oligo- or polypeptide that is capable of binding a        ligand. Preferably, the domain will be capable of interacting        with a cell surface molecule. For example, the extracellular        ligand-binding domain may be chosen to recognize a ligand that        acts as a cell surface marker on target cells associated with a        particular disease state. Thus examples of cell surface markers        that may act as ligands include those associated with viral,        bacterial and parasitic infections, autoimmune disease and        cancer cells.

The term “subject” or “patient” as used herein includes all members ofthe animal kingdom including non-human primates and humans.

The above written description of the invention provides a manner andprocess of making and using it such that any person skilled in this artis enabled to make and use the same, this enablement being provided inparticular for the subject matter of the appended claims, which make upa part of the original description.

Where a numerical limit or range is stated herein, the endpoints areincluded. Also, all values and subranges within a numerical limit orrange are specifically included as if explicitly written out.

The above description is presented to enable a person skilled in the artto make and use the invention, and is provided in the context of aparticular application and its requirements. Various modifications tothe preferred embodiments will be readily apparent to those skilled inthe art, and the generic principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the invention. Thus, this invention is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein.

Having generally described this invention, a further understanding canbe obtained by reference to certain specific examples, which areprovided herein for purposes of illustration only, and are not intendedto be limiting unless otherwise specified.

EXAMPLES Example 1 TALE-Nucleases Cleaving the Human GR Gene

6 heterodimeric TALE-nucleases targeting exons of the human GR gene weredesigned and produced. Table 1 below indicates the target sequencescleaved by each TALE-nuclease. GR TALE-nuclease was composed of twoindependent entities (called half TALE-nucleases) each containing arepeat sequence engineered to bind and cleave GR target sequencesconsisting of two 17-bp long sequences (called half targets) separatedby a 15-bp spacer.

TABLE 1 Description of the GR TALE-nucleases and sequences ofthe TALE-nucleases target sites in the human GR gene. Target Half TALE-name Target sequence Repeat sequence nuclease sequence GRex2TATTCACTGATGGA Repeat GRex2-LPT9-L1 GRex2-L TALEN CTC (SEQ ID NO: 7)(SEQ ID NO: 19) caaagaatcattaac Repeat -GRex2-LPT9- GRex2-R TALENTCCTGGTAGAGAAG R1 (SEQ ID NO: 20) AAA (SEQ ID NO: 8) (SEQ ID NO: 1)GRex3T2 TGCCTGGTGTGCTC Repeat -GRex3T2-L1 GRex3T2-L TGA (SEQ ID NO: 9)TALEN tgaagcttcaggatg (SEQ ID NO: 21) TCATTATGGAGTCT Repeat -GRex3T2-R1GRex3T2-R TAA (SEQ ID NO: 10) TALEN (SEQ ID NO: 2) (SEQ ID NO: 22)GRex3T4 TGCTCTGATGAAGC Repeat -GRex3T4-L1 GRex3T4-L TTC (SEQ ID NO: 11)TALEN aggatgtcattatgg (SEQ ID NO: 23) AGTCTTAACTTGTG Repeat -GRex3T4-R1GRex3T4-R GAA (SEQ ID NO: 12) TALEN (SEQ ID NO: 3) (SEQ ID NO: 24)GRex5T1 TGGTGTCACTGTTG Repeat -GRex5T1- GRex5T1-L GAG LPT8-L1 TALENgttattgaacctgaa (SEQ ID NO: 13) (SEQ ID NO: 25) GTGTTATATGCAGGRepeat -GRex5T1- GRex5T1-R ATA LPT8-R1 TALEN (SEQ ID NO: 4)(SEQ ID NO: 14) (SEQ ID NO: 26) GRex5T2 TATGATAGCTCTGTRepeat -GRex5T2-L1 GRex5T2-L TCC (SEQ ID NO: 15) TALEN agactcaacttggag(SEQ ID NO: 27) GATCATGACTACGC Repeat GRex5T2-R1 GRex5T2-R TCA(SEQ ID NO: 16) TALEN (SEQ ID NO: 5) (SEQ ID NO: 28) GRex5T3TTATATGCAGGATA Repeat -GRex5T3-L1 GRex5T3-L TGA (SEQ ID NO: 17) TALENtagctctgttccaga (SEQ ID NO: 29) CTCAACTTGGAGGA Repeat -GRex5T3-R1GRex5T3-R TCA (SEQ ID NO: 18) TALEN (SEQ ID NO: 6) (SEQ ID NO: 30)

The amino acid sequences of the N-terminal, C-terminal domains andrepeat are based on the AvrBs3 TALE (ref: GenBank: X16130.1). TheC-terminal and the N-terminal domains are separated by two BsmBIrestriction sites. The repeat arrays (SEQ ID NO: 7 to 18), targeting thedesired sequences (SEQ ID NO: 1 to 6) were synthesized using a solidsupport method composed of consecutive restriction/ligation/washingsteps (International PCT application WO2013/017950). In brief, the firstblock (coding for a di-repeat) was immobilized on a solid supportthrough biotin/streptavidin interaction, the second block (tri-repeat)was then ligated to the first and after SfaNI digestion a third bloc(tri-repeat) was coupled. The process was repeated using tri- ordi-repeat blocks upon obtaining the desired repeat array. The productwas then cloned in a classical pAPG10 cloning plasmid for amplificationin E. coli and sequenced. The repeat array sequences thus obtained weresubcloned in a yeast expression TALE vector using type IIS restrictionenzymes BsmBI for the receiving plasmid and BbvI and SfaNI for theinserted repeat sequence. DNA coding for the half TALE-nuclease,containing a TALE derived DNA binding domain fused to the catalyticdomain of the FokI restriction enzyme, was amplified in E. coli,recovered by standard miniprep techniques and sequenced to assess theintegrity of the insert.

Activity of GR TALE-Nucleases in Yeast:

Nuclease activity of the six GR-TALE-nucleases were tested at 37° C. and30° C. in our yeast SSA assay previously described (International PCTApplications WO 2004/067736 and in (Epinat, Arnould et al. 2003; Chames,Epinat et al. 2005; Arnould, Chames et al. 2006; Smith, Grizot et al.2006) on targets containing the two TALE target sequences facing eachother on the DNA strand separated by a spacer of 15 bps resulting in SEQID NO: 1 to 6. All the yeast target reporter plasmids containing theTALE-nuclease DNA target sequences were constructed as previouslydescribed (International PCT Applications WO 2004/067736 and in (Epinat,Arnould et al. 2003; Chames, Epinat et al. 2005; Arnould, Chames et al.2006; Smith, Grizot et al. 2006). TALE-nuclease cleavage activitylevels, in yeast, of individual clones on the targets are presented intable 2.

TABLE 2 Cleavage activity of the GR TALE-nucleases in yeast. Values arecomprised between 0 and 1. Maximal value is 1. Half TALE-nuclease yeastTarget transfected gal37° C. yeast gal30° C. GRex2 Grex2-L TALEN 1 1Grex2-R TALEN GRex3T2 GRex3T2-L TALEN 0.92 0.87 GRex3T2-R TALEN GRex3T4GRex3T4-L TALEN 0.94 0.87 GRex3T4-R TALEN GRex5T1 GRex5T1-L TALEN 0.480.36 GRex5T1-R TALEN GRex5T2 GRex5T2-L TALEN 0.97 0.91 GRex5T2-R TALENGRex5T3 GRex5T3-L TALEN 1 0.98 GRex5T3-R TALEN

Activity of GR TALE-Nucleases in HEK293 Cells:

Each TALE-nuclease construct was subcloned using restriction enzymedigestion in a mammalian expression vector under the control of apEF1alpha long promoter.

One million HEK293 cells were seeded one day prior to transfection.Cells were co-transfected with 2.5 μg of each of two plasmids encodingleft and right half of GRex2, GRex3T2, GRex3T4, GRex5T1, GRex5T2 orGRex5T3 TALE-nuclease recognizing the two half targets genomic sequencesof interest in the GR gene under the control of EF1alpha promoter using25 μL of lipofectamine (Invitrogen) according to the manufacturer'sinstructions. As a control, cells were co-transfected with 2.5 μg ofeach of the two plasmids encoding the left and the right half ofTALE-nucleases targeting the T-cell receptor alpha constant chain region(TRAC_T01) target site ((TRAC_T01-L and -R TALE-nuclease (SEQ ID NO: 41and SEQ ID NO: 42, TRAC_T01 target site (SEQ ID NO: 37)) under thecontrol of EF1alpha promoter. The double strand break generated byTALE-nucleases in GR coding sequence induces non homologous end joining(NHEJ), which is an error-prone mechanism. Activity of TALE-nucleases ismeasured by the frequency of insertions or deletions at the genomiclocus targeted.

2 or 7 days post transfection cells were harvested and locus specificPCRs were performed on genomic DNA extracted using the followingprimers: 5′-CCATCTCATCCCTGCGTGTCTCCGACTCAG-3′ (forward adaptatorsequence)-10N (TAG)-locus specific forward sequence for GR exon 2:5′-GGTTCATTTAACAAGCTGCC-3′ (SEQ ID NO: 31), for GR exon 3:5′-GCATTCTGACTATGAAGTGA-3′ (SEQ ID NO: 32) and for GR exon 5:5′-TCAGCAGGCCACTACAGGAGTCTCACAAG-3′ (SEQ ID NO: 33) and the reverseprimer 5′-CCTATCCCCTGTGTGCCTTGGCAGTCTCAG-3′ (reverse adaptorsequence)-locus specific reverse sequence for GR exon 2:5′-AGCCAGTGAGGGTGAAGACG-3′ (SEQ ID NO: 34), for GR exon 3:5′-GGGCTTTGCATATAATGGAA-3′ (SEQ ID NO: 35) and for GR exon 5:5′-CTGACTCTCCCCTTCATAGTCCCCAGAAC-3′ (SEQ ID NO: 36).

PCR products were sequenced by a 454 sequencing system (454 LifeSciences). Approximately 10,000 sequences were obtained per PCR productand then analyzed for the presence of site-specific insertion ordeletion events. Table 3 indicates the percentage of the sequencesshowing insertions or deletions at the TALE-nuclease target site amongthe total number of sequences in the sample. In table 3 are listed forGRex2, GRex3T2 and GRex3T4 the results of a representative experiment.

In all cases tested, the % of mutagenesis was similar at day 7 comparedto the one of the sample at day 2 post transfection. The nature of themutagenic events was also analyzed, revealing a majority of deletions inall cases compared to insertions.

TABLE 3 Percentage of targeted mutagenesis at endogenous TALE-nucleaseTarget sites in HEK293 cells. % Indels at 2 days % Indels at 7 days %Indels at 2 days with with with TRAC_T01 GR TALE-nuclease GRTALE-nuclease TALE-nuclease Target transfection transfection controltransfection GRex2 20.3 24.9 0.5 GRex3T2 9.3 9.8 0 GRex3T4 19 18.3 0.0GRex5T1 11.2 NA 0.7 GRex5T2 3.4 NA 0 GRex5T3 8.3 NA 0

Activity of GR TALE-Nucleases in Primary T Lymphocytes:

Each TALE-nuclease construct was subcloned using restriction enzymedigestion in an expression vector under the control of a T7 promoter.

mRNA encoding TALE-nucleases cleaving GR genomic sequences weresynthesized from each plasmid carrying the coding sequences downstreamfrom the T7 promoter. T lymphocytes isolated from peripheral blood wereactivated for 5 days using anti-CD3/CD28 activator beads (Lifetechnologies) and 5 million cells were transfected by electroporationwith 10 μg of each of 2 mRNAs encoding both half TALE-nucleases using aCytoLVT-P instrument (BTX-Harvard apparatus). T cells transfected with10 μg of each of the 2 mRNAs encoding both half TALE-nucleases targetingthe CD52 gene (CD52_T02-L and -R TALEN (SEQ ID NO: 55 and 56), targetsequence CD52_T02 SEQ ID NO: 40) are used as a control.

3 and 7 days after transfection, genomic DNA was isolated fromtransfected cells and locus specific PCRs were performed using theprimers described previously. PCR products were sequenced by a 454sequencing system (454 Life Sciences). Approximately 10,000 sequenceswere obtained per PCR product and then analyzed for the presence ofsite-specific insertion or deletion events; results are in Table 4.

TABLE 4 Percentage of targeted mutagenesis at endogenous TALE-nucleasetarget sites in primary T lymphocytes. % Indels at day 3 % Indels at day7 % Indels at day 3 with GR with GR with CD52 TALE nuclease TALEnuclease TALE-nuclease Target transfection transfection controltransfection GRex2 26.2 30.7 0.7 GRex3T2 1.09 0.86 0.02 GRex3T4 6.3 6.930 GRex5T1 0.04 0.035 0.05 GRex5T2 1.3 1.0 0.22 GRex5T3 17.4 NA 0.41

Example 2 TALE-Nucleases Cleaving the Human CD52 Gene, the Human T-CellReceptor Alpha Constant Chain (TRAC) and the Human T-Cell Receptor BetaConstant Chains 1 and 2 (TRBC)

As described in example 1, heterodimeric TALE-nucleases targetingrespectively CD52, TRAC and TRBC genes were designed and produced. Thetargeted genomic sequences consist of two 17-bp long sequences (calledhalf targets) separated by an 11 or 15-bp spacer. Each half-target isrecognized by repeats of half TALE-nucleases listed in table 5. Thehuman genome contains two functional T-cell receptor beta chains (TRBC1and TRBC2). During the development of alpha/beta T lymphocytes, one ofthese two constant chains is selected in each cell to be spliced to thevariable region of TCR-beta and form a functional full length betachain. The 2 TRBC targets were chosen in sequences conserved betweenTRBC1 and TRBC2 so that the corresponding TALE-nuclease would cleaveboth TRBC1 and TRBC2 at the same time.

TABLE 5 Description of the CD52, TRAC and TRBC TALE-nucleasesand sequences of the TALE-nucleases targetsites in the human corresponding genes. Target Target sequenceRepeat sequence Half TALE-nuclease TRAC_T01 TTGTCCCACAGATATCC RepeatTRAC_T01-L Agaaccctgaccctg TRAC_T01-L TALEN CCGTGTACCAGCTGAGA(SEQ ID NO: 41) (SEQ ID NO: 49) (SEQ ID NO: 37) Repeat TRAC_T01-RTRAC_T01-R TALEN (SEQ ID NO: 42) (SEQ ID NO: 50) TRBC_T01TGTGTTTGAGCCATCAG Repeat TRBC_T01-L aagcagagatctccc TRBC_T01-L TALENACACCCAAAAGGCCACA (SEQ ID NO: 43) (SEQ ID NO: 51) (SEQ ID NO: 38) RepeatTRBC_T01-R TRBC_T01-R TALEN (SEQ ID NO: 44) (SEQ ID NO: 52) TRBC_T02TTCCCACCCGAGGTCGC Repeat TRBC_T02-L tgtgtttgagccatca TRBC_T02-L TALENGAAGCAGAGATCTCCCA (SEQ ID NO: 45) (SEQ ID NO: 53) (SEQ ID NO: 39) RepeatTRBC_T02-R TRBC_T02-R TALEN (SEQ ID NO: 46) (SEQ ID NO: 54) CD52_T02TTCCTCCTACTCACCAT Repeat CD52_T02-L TALEN cagcctcctggttat CD52_T02-L(SEQ ID NO: 55) GGTACAGGTAAGAGCAA (SEQ ID NO: 47) (SEQ ID NO: 40) RepeatCD52_T02-R TALEN CD52_T02-R (SEQ ID NO: 56) (SEQ ID NO: 48)

Other target sequences in TRAC and CD52 genes have been designed, whichare displayed in Table 6.

TABLE 6 Additional target sequences for TRAC and CD52 TALE-nucleases.Target Target sequence TRAC_T02 TTTAGAAAGTTCCTGTG atgtcaagctggtcgAGAAAAGCTTTGAAACA (SEQ ID NO: 57) TRAC_T03 TCCAGTGACAAGTCTGTctgcctattcaccga TTTTGATTCTCAAACAA (SEQ ID NO: 58) TRAC_T04TATATCACAGACAAAAC tgtgctagacatgag GTCTATGGACTTCAAGA (SEQ ID NO: 59)TRAC_T05 TGAGGTCTATGGACTTC aagagcaacagtgct GTGGCCTGGAGCAACAA(SEQ ID NO: 60) CD52_T01 TTCCTCTTCCTCCTAC caccatcagcctcctTTACCTGTACCATAAC (SEQ ID NO: 61) CD52_T04 TTCCTCCTACTCACCA cagcctcctggTCTTACCTGTACCATA (SEQ ID NO: 62) CD52_T05 TCCTACTCACCATCAG ctcctggttatTTGCTCTTACCTGTAC (SEQ ID NO: 63) CD52_T06 TTATCCCACTTCTCCTctacagatacaaact TTTTGTCCTGAGAGTC (SEQ ID NO: 64) CD52_T07TGGACTCTCAGGACAA acgacaccagccaaa TGCTGAGGGGCTGCTG (SEQ ID NO: 65)

Activity of CD52-TALE-Nuclease, TRAC-TALE-Nuclease andTRBC-TALE-Nuclease in HEK293 Cells

Each TALE-nuclease construct was subcloned using restriction enzymedigestion in a mammalian expression vector under the control ofpEF1alpha long promoter. One million HEK293 cells were seeded one dayprior to transfection. Cells were co-transfected with 2.5 μg of each ofthe two plasmids encoding the TALE-nucleases recognizing the two halftargets in the genomic sequence of interest in the CD52 gene, T-cellreceptor alpha constant chain region (TRAC) or T-cell receptor betaconstant chain region (TRBC) under the control of the EF1-alpha promoteror 5 μg of a control pUC vector (pCLS0003) using 25 μl of lipofectamine(Invitrogen) according to the manufacturer's instructions. The doublestranded cleavage generated by TALE-nucleases in CD52 or TRAC codingsequences is repaired in live cells by non homologous end joining(NHEJ), which is an error-prone mechanism. Activity of TALE-nucleases inlive cells is measured by the frequency of insertions or deletions atthe genomic locus targeted. 48 hours after transfection, genomic DNA wasisolated from transfected cells and locus specific PCRs were performedusing the following primers: 5′-CCATCTCATCCCTGCGTGTCTCCGACTCAG (forwardadaptor sequence)-10N (TAG)-locus specific forward sequence for CD52:5′-CAGATCTGCAGAAAGGAAGC-3′ (SEQ ID NO: 66), for TRAC:5′-ATCACTGGCATCTGGACTCCA-3′ (SEQ ID NO: 67), for TRBC1:5′-AGAGCCCCTACCAGAACCAGAC-3′ (SEQ ID NO: 68), or for TRBC2:5′-GGACCTAGTAACATAATTGTGC-3′ (SEQ ID NO: 69), and the reverse primer5′-CCTATCCCCTGTGTGCCTTGGCAGTCTCAG (reverse adaptor sequence)-endogenouslocus specific reverse sequence for CD52: 5′-CCTGTTGGAGTCCATCTGCTG-3′(SEQ ID NO: 70), for TRAC: 5′-CCTCATGTCTAGCACAGTTT-3′ (SEQ ID NO: 71),for TRBC1 and TRBC2: 5′-ACCAGCTCAGCTCCACGTGGT-3′ (SEQ ID NO: 72). PCRproducts were sequenced by a 454 sequencing system (454 Life Sciences).Approximately 10,000 sequences were obtained per PCR product and thenanalyzed for the presence of site-specific insertion or deletion events;results are in Table 7.

TABLE 7 Percentages of indels for TALE-nuclease targeting CD52_T02,TRAC_T01, TRBC_T01 and TRBC_T02 targets. % Indels with TALE-nuclease %Indels with pUC Target transfection control transfection CD52_T02 28.00.9 TRBC_T01 41.9 0.3 TRBC_T01 in constant chain 1 3.81 0 TRBC_T01 inconstant chain 2 2.59 0 TRBC_T02 in constant chain 1 14.7 0 TRBC_T02 inconstant chain 1 5.99 0

Activity of CD52-TALE-Nuclease, TRBC-TALE-Nuclease andTRAC-TALE-Nuclease in Primary T Lymphocytes

Each TALE-nuclease construct was subcloned using restriction enzymedigestion in a mammalian expression vector under the control of the T7promoter.

mRNA encoding TALE-nuclease cleaving CD52 TRAC and TRBC genomic sequencewere synthesized from plasmid carrying the coding sequences downstreamfrom the T7 promoter. T lymphocytes isolated from peripheral blood wereactivated for 5 days using anti-CD3/CD28 activator beads (Lifetechnologies) and 5 million cells were then transfected byelectroporation with 10 μg of each of 2 mRNAs encoding both halfTALE-nuclease (or non coding RNA as controls) using a CytoLVT-Pinstrument. As a consequence of the insertions and deletions induced byNHEJ, the coding sequence for CD52 and/or TRAC will be out of frame in afraction of the cells resulting in non-functional genes. 5 days afterelectroporation, cells were labeled with fluorochrome-conjugatedanti-CD52 or anti-TCR antibody by flow cytometry for the presence ofCD52 or TCR at their cell surface. Since all T lymphocytes expanded fromperipheral blood normally express CD52 and TCR, the proportion ofCD52-negative or TCR-negative cells is a direct measure of TALE-nucleaseactivity. In table 8 are listed the results of a representativeexperiment. The table 9 shows the results of a representative experimenttesting the efficiency of TRBC TALE-nucleases.

TABLE 8 Percentages of CD52-negative, TCR-negative and CD52/TCR-doublenegative T lymphocytes after transfection of correspondingTALE-nuclease-expressing polynucleotides. % CD52-negative % TCR-negative% CD52/TCR double ARN transfected cells cells negative cells non codingRNA 1.21 1.531 0.111 TALEN CD52_T02 49.2 1.6 0.78 TALEN TRAC_T01 2.1644.8 0.97 TALEN CD52_T02 + TALEN 29.3 39.6 15.5 TRAC_T01

TABLE 9 Percentages of TCR-negative T lymphocytes after transfection ofTRBC TALE- nuclease-expressing polynucleotides. ARN transfected %TCR-negative cells no RNA 1.22 TALEN TRBC_T01 6.52 TALEN TRBC_T02 23.5Functional Analysis of T Cells with Targeted CD52 Gene

The goal of CD52 gene inactivation is to render T lymphocytes resistantto anti-CD52 antibody mediated immunosuppression. As described in theprevious paragraph, T lymphocytes were transfected with mRNA encodingTALE-nuclease cleaving CD52. 7 days after transfection, cells weretreated with 50 μg/ml anti-CD52 monoclonal antibody (or rat IgG ascontrol) with or without 30% rabbit complement (Cedarlane). After 2hours of incubation at 37° C., the cells were labeled with afluorochrome-conjugated anti-CD52 antibody together with a fluorescentviability dye (eBioscience) and analyzed by flow cytometry to measurethe frequency of CD52-positive and CD52-negative cells among live cells.FIG. 6 shows the result of a representative experiment, demonstratingthat CD52-negative cells are completely resistant to complement-mediatedanti-CD52 antibody toxicity.

Functional Analysis of T Cells with Targeted TRAC Gene

The goal of TRAC gene inactivation is to render T lymphocytesunresponsive to T-cell receptor stimulation. As described in theprevious paragraph, T lymphocytes were transfected with mRNA encodingTALE-nuclease cleaving TRAC or CD52. 16 days after transfection, cellswere treated with up to 5 μg/ml of phytohemagglutinin (PHA,Sigma-Aldrich), a T-cell mitogen acting through the T cell receptor.Cells with a functional T-cell receptor should increase in sizefollowing PHA treatment. After three days of incubation, cells werelabeled with a fluorochrome-conjugated anti-CD52 or anti-TCR antibodyand analyzed by flow cytometry to compare the cell size distributionbetween TCR-positive and TCR-negative cells, or between CD52-positiveand CD52-negative cells. FIG. 7 shows that TCR-positive cellssignificantly increase in size after PHA treatment whereas TCR-negativecells have the same size as untreated cells indicating that TRACinactivation rendered them unresponsive to TCR-signaling By contrast,CD52-positive and CD52-negative increase in size to same extent.

Functional Analysis of T Cells with Targeted CD52 and TRAC Genes

To verify that genome engineering did not affect the ability of T cellsto present anti-tumor activity when provided with a chimeric antigenreceptor (CAR), we transfected T cells that had been targeted withCD52-TALE-nuclease and TRAC-TALE-nuclease with 10 μg of RNA encoding ananti-CD19 CAR (SEQ ID NO: 73). 24 hours later, T cells were incubatedfor 4 hours with CD19 expressing Daudi cells. The cell surfaceupregulation of CD107a, a marker of cytotoxic granule release by Tlymphocytes (called degranulation) was measured by flow cytometryanalysis (Betts, Brenchley et al. 2003). The results are included inFIG. 8 and show that CD52-negative/TCRαβ-negative cells andCD52-positive/TCRαβ-positive have the same ability to degranulate inresponse to PMA/ionomycin (positive control) or CD19+ Daudi cells. CD107upregulation is dependent on the presence of a CD19+. These data suggestthat genome engineering has no negative impact on the ability of T cellsto mount a controlled anti-tumor response.

Genomic Safety of CD52-TALE-Nuclease and TRAC-TALE-Nuclease in Primary TLymphocytes

As our constructs include nuclease subunits, an important question iswhether multiple TALE-nuclease transfection can lead to genotoxicity andoff-target cleavage at ‘close match’ target sequences or by mispairingof half-TALE-nucleases. To estimate the impact of TRAC-TALE-nuclease andCD52-TALE-nuclease on the integrity of the cellular genomes, we listedsequences in the human genome that presented the potential for off-sitecleavage. To generate this list, we identified all the sequences in thegenome with up to 4 substitutions compared to the original half targetsand then identified the pairs of potential half targets in a head tohead orientation with a spacer of 9 to 30 bp from each other. Thisanalysis included sites potentially targeted by homodimers of onehalf-TALE-nuclease molecule or heterodimers formed by one CD52 halfTALE-nuclease and one TRAC half-TALE-nuclease. We scored the potentialoff-site targets based on the specificity data taking into account thecost of individual substitutions and the position of the substitutions(where mismatches are better tolerated for bases at the 3′ end of thehalf target). We obtained 173 unique sequences with a score reflectingan estimation of the likelihood of cleavage. We selected the 15 topscores and analyzed by deep sequencing the frequency of mutations foundat these loci in T cells simultaneously transfected with CD52 and TRACTALE-nuclease and purified by magnetic separation as CD52-negative,TCRαβ-negative. Results are in FIG. 9. The highest frequency ofinsertion/deletion is 7×10⁻⁴. These results make the putative offsitetarget at least 600 times less likely to be mutated than the intendedtargets. The TALE-nuclease reagents used in this study therefore appearextremely specific.

Example 3 TALE-Nucleases Cleaving the Human CTLA4 Gene and the HumanPDCD1 Gene

As described in example 1, heterodimeric TALE-nucleases targetingrespectively PDCD1 and CTLA4 genes were designed and produced. Thetargeted genomic sequences consist of two 17-bp long sequences (calledhalf targets) separated by an 11 or 15-bp spacer. Each half-target isrecognized by repeats of half TALE-nucleases listed in table 10.

TABLE 10Description of the CTLA4 and PDCD1 TALE-nucleases and sequences ofthe TALE-nucleases target sites in the human corresponding genes.Half TALE- Target Target sequence Repeat sequence nuclease CTLA4_T01TGGCCCTGCACTCTCCT Repeat CTLA4_T01-L gttttttcttctctt CTLA4_T01-L TALENCATCCCTGTCTTCTGCA (SEQ ID NO: 79) (SEQ ID NO: 89) (SEQ ID NO: 74) RepeatCTLA4_T01-R CTLA4_T01-R TALEN (SEQ ID NO: 80) (SEQ ID NO: 90) CTLA4_T03TTTTCCATGCTAGCAAT Repeat CTLA4_T03-L gcacgtggcccagcc CTLA4_T03-L TALENTGCTGTGGTACTGGCCA (SEQ ID NO: 81) (SEQ ID NO: 91) (SEQ ID NO: 75) RepeatCTLA4_T03-R CTLA4_T03-R TALEN (SEQ ID NO: 82) (SEQ ID NO: 92) CTLA4_T04TCCATGCTAGCAATGCA Repeat CTLA4_T04-L cgtggcccagcctgc CTLA4_T04-L TALENTGTGGTACTGGCCAGCA (SEQ ID NO: 84) (SEQ ID NO: 93) (SEQ ID NO: 76) RepeatCTLA4_T04-R CTLA4_T04-R TALEN (SEQ ID NO: 85) (SEQ ID NO: 94) PDCD1_T01TTCTCCCCAGCCCTGCT Repeat PDCD1_T01-L cgtggtgaccgaagg PDCD1_T01-L TALENGGACAACGCCACCTTCA (SEQ ID NO: 86) (SEQ ID NO: 95) (SEQ ID NO: 77) RepeatPDCD1_T01-R PDCD1_T01-R TALEN (SEQ ID NO: 87) (SEQ ID NO: 96) PDCD1_T03TACCTCTGTGGGGCCAT Repeat PDCD1_T03-L ctccctggcccccaa PDCD1_T03-L TALENGGCGCAGATCAAAGAGA (SEQ ID NO: 88) (SEQ ID NO: 97) (SEQ ID NO: 78) RepeatPDCD1_T03-R PDCD1_T03-R TALEN (SEQ ID NO: 89) (SEQ ID NO: 98

Activity of CTLA4-TALE-Nuclease and PDCD1-TALE-Nuclease in HEK293 Cells

Each TALE-nuclease construct was subcloned using restriction enzymedigestion in a mammalian expression vector under the control of thepEF1alpha long promoter. One million HEK293 cells were seeded one dayprior to transfection. Cells were co-transfected with 2.5 μg of each oftwo plasmids encoding the TALE-nucleases recognizing the two halftargets in the genomic sequence of interest in the PDCD1 and CTLA-4 geneunder the control of the EF1-alpha promoter or 5 μg of a control pUCvector (pCLS0003) using 25 μl of lipofectamine (Invitrogen) according tothe manufacturer's instructions. The double stranded cleavage generatedby TALE-nucleases in PDCD1 or CTLA-4 coding sequences is repaired inlive cells by non homologous end joining (NHEJ), which is an error-pronemechanism. Activity of TALE-nucleases in live cells is measured by thefrequency of insertions or deletions at the genomic locus targeted. 48hours after transfection, genomic DNA was isolated from transfectedcells and locus specific PCRs were performed using the followingprimers: 5′-CCATCTCATCCCTGCGTGTCTCCGACTCAG (forward adaptorsequence)-10N (TAG)-locus specific forward sequence for CTLA4_T01:5′-CTCTACTTCCTGAAGACCTG-3′ (SEQ ID NO: 99), for CTLA4_T03/T04:5′-ACAGTTGAGAGATGGAGGGG-3′ (SEQ ID NO: 100), for PDCD1_T01:5′-CCACAGAGGTAGGTGCCGC-3′ (SEQ ID NO: 101) or for PDCD1_T03:5′-GACAGAGATGCCGGTCACCA-3′ (SEQ ID NO: 102) and the reverse primer5′-CCTATCCCCTGTGTGCCTTGGCAGTCTCAG (reverse adaptor sequence)-endogenouslocus specific reverse sequence for CTLA4_T01:5′-TGGAATACAGAGCCAGCCAA-3′ (SEQ ID NO: 103), for CTLA4_T03/T04:5′-GGTGCCCGTGCAGATGGAAT-3′ (SEQ ID NO: 104), for PDCD1_T01:5′-GGCTCTGCAGTGGAGGCCAG-3′ (SEQ ID NO: 105) or for PDCD1_T03:5′-GGACAACGCCACCTTCACCT-3′ (SEQ ID NO: 106).

PCR products were analyzed by T7-endonuclease assay: briefly, afterdenaturation and reannealing of the PCR product, T7 endonuclease willspecifically digest mismatched DNA composed of wild type and mutatedstrands. The digestion product is then resolved by polyacrylamide gelelectrophoresis. The presence of a digested product is indicative ofmutated sequences induced by TALE-nuclease activity. Results aredisplayed in FIG. 10 where arrows point to the digested PCR products.They demonstrate that PDCD1_T1, PDCD1_T3, CTLA4_T1, CTLA4_T3 andCTLA4_T4 TALE-nucleases all exhibit mutagenic nuclease activity at theirtarget sites.

Example 4 pTalpha Permits CD3 Surface Expression in Inactivated TCRAlpha T Lymphocytes

Description of the Different preTalpha Versions:

The human pTalpha gene encodes a transmembrane glycoprotein comprisingan extracellular Ig-like domain, a hydrophobic transmembrane domain anda large C-terminal intracytoplasmic tail. Different versions derivedfrom human pTalpha glycoprotein have been designed and are described inTable 11 and represented in FIG. 11.

TABLE 11 Description of a subset of pTalpha constructs SEQ PTalphaversions Description ID pTalpha-FL Full-length of human pTalphaglycoprotein 107 pTalpha-Δ18 Truncated Human pTalpha glycoproteinlacking 18 residues 108 from the C-terminus. pTalpha-Δ48 Truncated HumanpTalpha glycoprotein lacking 48 residues 109 from the C-terminus.pTalpha-Δ62 Truncated Human pTalpha glycoprotein lacking 62 residues 110from the C-terminus. pTalpha-Δ78 Truncated Human pTalpha glycoproteinlacking 78 residues 111 from the C-terminus. pTalpha-Δ92 Truncated HumanpTalpha glycoprotein lacking 92 residues 112 from the C-terminus.pTalpha-Δ110 Truncated Human pTalpha glycoprotein lacking 110 113residues from the C-terminus. pTalpha-Δ114 Truncated Human pTalphaglycoprotein lacking 114 114 residues from the C-terminus.pTalpha-FL-CD28 Full-length of human pTalpha glycoprotein fused in C-115 terminus with CD28 activation domain. pTalpha-FL-CD8 Full-length ofhuman pTalpha glycoprotein fused in C- 116 terminus with CD8 activationdomain. pTalpha-FL-4-1BB Full-length of human pTalpha glycoprotein fusedin C- 117 terminus with 4-1BB activation domain.. pTalpha-Δ48-CD28pTalpha-Δ48 glycoprotein fused in C-terminus with CD28 118 activationdomain. pTalpha-Δ48-CD8 pTalpha-Δ48 glycoprotein fused in C-terminuswith CD8 119 activation domain. pTalpha-Δ48-41BB pTalpha-Δ48glycoprotein fused in C-terminus with 4-1BB 120 activation domain.pTalpha- pTalpha-Δ114 glycoprotein fused in C-terminus with the 121Δ114/TCRα.IC intracellular domain of TCRalpha pTalpha- pTalphaextracellular domain fused in C-terminus with the 122 EC/TCRα.TM.ICtransmembrane and intracellular domain of TCRalpha. pTalpha-Δ48-pTalpha-Δ48 glycoprotein with mutated residue W46R. 123 1xMUTpreTalpha-Δ48- pTalpha-Δ48 glycoprotein with mutated residues D22A, 1244xMUT K24A, R102A, R117A

The different preTalpha constructs tested include:

-   -   1) pTalpha deletion mutants: Different deletions were generated        in the intracellular cytoplasmic tail of the human pTalpha        protein (which comprises 114 amino acids) (SEQ ID NO: 107). The        constructs tested include the full length version of the protein        (FL) and mutants in which 18, 48, 62, 78, 92, 110 and 114 amino        acids were deleted from the C-terminus of the protein (SEQ ID        NO: 108 to SEQ ID NO: 114).    -   2) pTalpha mutants containing intracellular activation domains:        The FL and Δ48 variants where fused to the CD8, CD28 or 41BB        intracellular activation domains at their C-terminus (SEQ ID NO:        115 to SEQ ID NO: 120).    -   3) pTalpha/TCRα chimeric mutants: In one of the constructs, the        TCRα intracellular domain (IC) was fused to a tail-less version        (Δ114) of pTalpha (SEQ ID NO: 121). A second construct was also        generated in which the pTalpha extracellular domain was fused to        the transmembrane (TM) and the IC domains from TCRα (SEQ ID NO:        122).    -   4) pTalpha dimerization mutants: Some mutations have been        described in the literature as being capable to alter the        oligomerisation/dimerisation ability of the preTCR complex.        These mutants are proposed to allow preTCR expression at the        cell surface, without inducing the constitutive signaling        (supposed to be induced upon preTCR oligomerization). The        mutations have been introduced in the pTalphaΔ48 variant and        are:        -   1×MUT: W46R (SEQ ID NO: 123)        -   4×MUT: D22A, K24A, R102A, R117A (SEQ ID NO: 124)            Activity of Different preTalpha Constructs in TRAC            Inactivated Jurkat Cells:

In order to screen different pTalpha variants for their ability torestore CD3 surface expression in TCRalpha inactivated cells, a cellline was generated in which the TCRalpha gene was disrupted using TALENtargeting TRAC. Jurkat cells (a T-cell leukemia cell line) weretransfected with plasmids coding for the TALEN cleaving TRAC usingCytoPulse electroporation, and the KO cells (TCR_(α/β) ^(NEG);CD3^(NEG)) where then purified by negative selection using CD3 magneticbeads. The KO population (JKT_KO×3 cells) was amplified and used forscreening of the different pTalpha variants. Screening was performed bytransfection of one million of JKT_KO×3 cells with 15 μg of plasmidcoding the different pTalpha variants under control of the EF1αpromoter, followed by analysis by flow cytometry of CD3 cell surfaceexpression 48 h after transfection. FIG. 12 is a representative exampleof the transfection efficiencies (% of BFP+ cells) and activity of theFL, Δ18 and Δ48 pTalpha constructs in JKT_KO×3 cells, based on the % ofCD3+ cells, determined by flow cytometry. The results from the differentconstructs are grouped in Table 12.

TABLE 12 Activity of the different pTalpha constructs in Jurkat TCRalpha inactivated cells. Activity was measured by flow cytometryanalysis of CD3 expression in jurkat TCR alpha inactivated cellstransfected with the different preTalpha constructs. Mutant ID %CD3_(LOW) SD 0 NEG 4.69 1.53 1 preTCRa-FL 31.18 4.15 2 preTCRα-Δ18 20.134.56 3 preTCRα-Δ48 44.86 3.90 4 preTCRα-Δ62 32.42 2.95 5 preTCRα-Δ7824.75 3.87 6 preTCRα-Δ92 20.63 3.70 7 preTCRα-Δ110 18.18 3.49 8preTCRα-Δ114 4.29 2.74 9 preTCRα-FL-CD8 18.16 5.30 10 preTCRα-FL-CD285.67 2.77 11 preTCRα-FL-41BB 27.27 3.66 12 preTCRα-Δ48-CD8 11.56 6.01 13preTCRα-Δ48-CD28 12.22 4.72 14 preTCRα-Δ48-41BB 35.93 4.55 15preTCRα-Δ114/TCRα.IC 3.94 1.95 16 preTCRα-EC/TCRα.TM.IC 17.80 4.47 17preTCRα-Δ48-1xMUT 26.88 4.37 18 preTCRα-Δ48-4xMUT 7.59 1.06Activity of pTalpha-FL and pTalpha-Δ48 in TCR Alpha Inactivated PrimaryT Lymphocytes:

In order to test the ability of pTalpha-FL and pTalpha-Δ48 versions toinduce CD3 surface expression in TCR alpha inactivated T lymphocytes,pTalpha-FL and pTalpha-Δ48 coding sequences were cloned into aself-inactivating pLV-SFFV-BFP-2A-PCTRA lentiviral vector that codes forBlue Fluorescent protein (BFP) under the SFFV promoter followed by theself-cleaving T2A peptide (FIG. 13).

T lymphocytes isolated from peripheral blood were activated for 72 hoursusing anti-CD3/CD28 activator beads (Life technologies) and 4.5 millioncells were transfected by electroporation with 10 μg mRNA encoding theTALE-nuclease targeting TCR alpha constant chain region (TRAC) using aCytoLVT-S instrument (BTX-Harvard Harbour). Two days afterelectroporation, T cells were transduced with either theLV-SFFV-BFP-2A-pTalpha-Δ48 or LV-SFFV-BFP-2A-control lentiviral vectors.CD3 negative and CD3low T cells were then purified using anti-CD3magnetic beads (Miltenyi Biotech). This experimental protocol isrepresented in FIG. 14A.

FIG. 14B represents flow cytometry analysis of TCRalpha/beta, CD3 cellsurface expression, and BFP expression on TCRalpha inactivated T cells(KO) transduced with either BFP-2A-pTalphaΔ48 (KO/Δ48) or control BFPlentiviral vector (KO/BFP) before and after purification with CD3 beads.TCRalpha inactivated cells transduced with the BFP-T2A-pTalpha-Δ48vector (BFP+ cells) show higher levels of CD3 compared to non transducedcells (BFP− cells). No differences are observed among cells transducedwith the control BFP vector. These results indicate that pTalphamediates restoration of CD3 expression at the cell surface of TCRalphainactivated cells. In contrast, TCRalpha/beta staining remains, asexpected, unchanged in cells transduced or not with the pTalpha-Δ48expressing vector.

pTalpha-Mediated CD3 Expression Supports Activation of TCR-DeficientT-Cells:

To determine the capacity of pTalpha to transduce cell activationsignals, expression of early and later activation markers was analyzedon TCR alpha inactivated T cells transduced with pTalpha-Δ48 andpTalpha-Δ48.41BB. TCR alpha inactivated T cells transduced withpTalpha-Δ48 and pTalpha-Δ48.41BB were generated from primary humanT-cells as described in previous section and in FIG. 14A.

To detect signaling via CD3, cells were re-activated usinganti-CD3/CD28-coated beads 3 days after purification of TCR alphainactivated T cells with CD3 beads (FIG. 14A). Cells were stained withfluorochrome-conjugated anti-CD69 (early activation marker) andanti-CD25 (late activation marker), 24 and 48 hours after re-activationrespectively and analyzed by flow cytometry (FIG. 15A-B). As representedin FIG. 15A-B, TCR alpha inactivated cells expressing pTalpha-Δ48(KO/pTα-Δ48) or pTalpha-Δ48.41BB (KO/pTα-Δ48.BB) show upregulation ofthe activation markers, to levels similar to those observed inTCRalpha/beta expressing cells (NEP: non electroporated cells).

Another indicator of T cell activation is an increase in cell size whichis sometimes referred to as “blasting”. The capacity of the preTCRcomplexes to induce “blasting” was measured by flow cytometry analysisof the cell size 72 hours after re-activation using anti-CD3/CD28-beads(FIG. 15C). Stimulation with anti-CD3/CD28 beads induced comparableincreases in cell size in cells expressing TCRalpha/beta complexes vs.cells expressing pTalpha-Δ48 or pTalpha-Δ48.41BB. Taken together, theseresults suggest that preTCR complexes are competent to transduce signalsthat efficiently couple to the mechanisms mediating activation markerupregulation.

pTalpha Mediated CD3 Expression Supports Expansion of TCR-DeficientPrimary T-Cells Using Stimulatory Anti-CD3/CD28 Antibodies

To evaluate the capacity of preTCR complexes to support long term cellproliferation, proliferation of cells generated as previously describedwas measured. Ten days after the initial activation, cells weremaintained in IL2 (non-Re-act) or in IL2 with anti-CD3/CD28 beads(Re-act). For each condition, cells were counted and analyzed by flowcytometry at the different time points to estimate the number of BFP+cells. The growth of TCRalpha inactivated cells (KO) transduced with BFPor BFP-T2A-preTCRα-Δ48 vectors was compared, and the fold induction ofthese cells was estimated with respect to the value obtained at day 2post re-activation. FIG. 16 shows the results obtained with twoindependent donors. In both cases, TCRalpha inactivated cells expressingpTalpha-Δ48 displayed greater expansion than TCR alpha inactivated cellsexpressing only the BFP control vector. For the second donor, TCRalphainactivated cells expressing pTalpha-Δ48.41BB or full-length pTalphawere also included, displaying also greater expansion than TCRalphainactivated cells expressing only the BFP control vector.

Example 5 Optimization of mRNA Transfection in T Cells Using CytopulseTechnology Determination of the Optimized Cytopulse Program

A first set of experiments were performed on non activated PBMCs inorder to determine a voltage range in which cells could be transfected.Five different programs were tested as described in Table 13.

TABLE 13 Different cytopulse programs used to determine the minimalvoltage required for electroporation in PBMC derived T-cells. Group 1Group 2 Group 3 Cytopulse duration Interval duration Interval durationInterval program Pulses V (ms) (ms) Pulses V (ms) (ms) Pulses V (ms)(ms) 1 1 600 0.1 0.2 1 600 0.1 100 4 130 0.2 2 2 1 900 0.1 0.2 1 900 0.1100 4 130 0.2 2 3 1 1200 0.1 0.2 1 1200 0.1 100 4 130 0.2 2 4 1 1200 0.110 1 900 0.1 100 4 130 0.2 2 5 1 900 0.1 20 1 600 0.1 100 4 130 0.2 2

3 or 6 million of cells were electroporated in 0.4 cm gap cuvette (30 or15×10⁶ cells/nil) with 20 μg of plasmids encoding GFP and controlplasmids pUC using the different Cytopulse programs. 24 hours postelectroporation, GFP expression was analyzed in electroporated cells byflow cytometry to determine the efficiency of transfection. The datashown in FIG. 17 indicates the minimal voltage required for plasmidelectroporation in PBMC derived T cells. These results demonstrate thatthe cytopulse program 3 and 4 allow an efficient transformation of Tcells (EP#3 and #4).

Electroporation of mRNA of Purified Tcells Activated

After determining the best cytopulse program that allows an efficientDNA electroporation of T cells, we tested whether this method wasapplicable to the mRNA electroporation.

5×10⁶ purified T cells preactivated 6 days with PHA/IL2 were resuspendedin cytoporation buffer T (BTX-Harvard apparatus) and electroporated in0.4 cm cuvettes with 10 μg of mRNA encoding GFP or 20 μg of plasmidsencoding GFP or pUC using the preferred cytopulse program as determinedin the previous section (table 14).

TABLE 14 Cytopulse program used to electroporate purified T-cells. Group1 Group 2 Group 3 Cytopulse duration Interval duration Interval durationInterval program Pulse V (ms) (ms) Pulse V (ms) (ms) Pulse V (ms) (ms) 31 1200 0.1 0.2 1 1200 0.1 100 4 130 0.2 2

48 h after transfection cells were stained with viability dye(eFluor-450) and the cellular viability and % of viable GFP+ cells wasdetermined by flow cytometry analysis (FIG. 18).

The data shown in FIG. 18 indicates that the electroporation of RNA withthe optimal condition determined here is no toxic and allowstransfection of more than 95% of the viable cells.

In synthesis, the whole dataset shows that T-cells can be efficientlytransfected either with DNA or RNA. In particular, RNA transfection hasno impact on cellular viability and allows uniform expression levels ofthe transfected gene of interest in the cellular population.

Efficient transfection can be achieved early after cellular activation,independently of the activation method used (PHA/IL-2 orCD3/CD28-coated-beads). The inventors have succeeded in transfectingcells from 72 h after activation with efficiencies of >95%. In addition,efficient transfection of T cells after thawing and activation can alsobe obtained using the same electroporation protocol.

mRNA Electroporation in Primary Human T Cells for TALE-NucleaseFunctional Expression

After demonstrating that mRNA electroporation allow efficient expressionof GFP in primary human T cells, we tested whether this method wasapplicable to the expression of other proteins of interest.Transcription activator-like effector nucleases (TALE-nuclease) aresite-specific nucleases generated by the fusion of a TAL DNA bindingdomain to a DNA cleavage domain. They are powerful genome editing toolsas they induce double-strand breaks at practically any desired DNAsequence. These double-strand breaks activate Non-homologous end-joining(NHEJ), an error-prone DNA repair mechanism, potentially leading toinactivation of any desired gene of interest. Alternatively, if anadequate repair template is introduced into the cells at the same time,TALE-nuclease-induced DNA breaks can be repaired by homologousrecombination, therefore offering the possibility of modifying at willthe gene sequence.

We have used mRNA electroporation to express a TALE-nuclease designed tospecifically cleave a sequence in the human gene coding for the alphachain of the T cell antigen receptor (TRAC). Mutations induced in thissequence are expected to result in gene inactivation and loss of TCRαβcomplex from the cell surface. TRAC TALE-nuclease RNA or non coding RNAas control are transfected into activated primary human T lymphocytesusing Cytopulse technology. The electroporation sequence consisted in 2pulses of 1200 V followed by four pulses of 130 V as described in Table14.

By flow cytometry analysis of TCR surface expression 7 days postelectroporation (FIG. 19, top panel), we observed that 44% of T cellslost the expression of TCRαβ. We analyzed the genomic DNA of thetransfected cells by PCR amplification of the TRAC locus followed by 454high throughput sequencing. 33% of alleles sequenced (727 out of 2153)contained insertion or deletion at the site of TALE-nuclease cleavage.FIG. 19 (bottom panel) shows examples of the mutated alleles.

These data indicate that electroporation of mRNA using cytopulsetechnology results in functional expression of TRAC TALE-nuclease.

Electroporation of T Cells with a Monocistronic mRNA Encoding for anAnti-CD19 Single Chain Chimeric Antigen Receptor (CAR):

5×10⁶ T cells preactivated several days (3-5) with anti-CD3/CD28 coatedbeads and IL2 were resuspended in cytoporation buffer T, andelectroporated in 0.4 cm cuvettes without mRNA or with 10 μg of mRNAencoding a single chain CAR (SEQ ID NO: 73) using the program describedin Table 14.

24 hours post electroporation, cells were stained with a fixableviability dye eFluor-780 and a PE-conjugated goat anti mouse IgG F(ab′)2fragment specific to assess the cell surface expression of the CAR onthe live cells. The data is shown in the FIG. 20. A indicates that thevast majority of the live T cells electroporated with the monocitronicmRNA described previously express the CAR at their surface. 24 hourspost electroporation, T cells were cocultured with Daudi (CD19⁺) cellsfor 6 hours and analyzed by flow cytometry to detect the expression ofthe degranulation marker CD107a at their surface (Betts, Brenchley etal. 2003).

The data shown in FIG. 20 indicates that the majority of the cellselectroporated with the monocistronic mRNA described previouslydegranulate in the presence of target cells expressing CD19. Theseresults clearly demonstrate that the CAR expressed at the surface ofelectroporated T cells is active.

Electroporation of T Cells with a Polycistronic mRNA Encoding for anAnti-CD19 Multisubunit Chimeric Antigen Receptor (CAR):

5×10⁶ T cells preactivated several days (3-5) with anti CD3/CD28 coatedbeads and IL2 were electroporated in cytoporation buffer T, andelectroporated in 0.4 cm cuvettes without mRNA or with 45 μg of mRNAencoding a multi-chain CAR (SEQ ID NO: 125, encoded by SEQ ID NO: 126,FIG. 21A and FIG. 4B (csm4)) using the program as described in Table 14.

24 hours post electroporation, cells were stained with a fixableviability dye eFluor-780 and a PE-conjugated goat anti mouse IgG F(ab′)2fragment specific to assess the cell surface expression of the CAR onthe live cells. The data shown in FIG. 21 indicates that the vastmajority of the live T cells electroporated with the polycistronic mRNAdescribed previously express the CAR at their surface.

24 hours post electroporation, T cells were cocultured with Daudi(CD19⁺) for 6 hours and analyzed by flow cytometry to detect theexpression of the degranulation marker CD107a at their surface. The datashown in FIG. 21 indicates that the majority of the cells electroporatedwith the polycistronic mRNA described previously degranulate in thepresence of target cells expressing CD19. These results clearlydemonstrate that the CAR expressed at the surface of electroporated Tcells is active.

LIST OF REFERENCES CITED IN THE DESCRIPTION

-   Arimondo, P. B., C. J. Thomas, et al. (2006). “Exploring the    cellular activity of camptothecin-triple-helix-forming    oligonucleotide conjugates.” Mol Cell Biol 26(1): 324-33.-   Arnould, S., P. Chames, et al. (2006). “Engineering of large numbers    of highly specific homing endonucleases that induce recombination on    novel DNA targets.” J Mol Biol 355(3): 443-58.-   Ashwell, J. D. and R. D. Klusner (1990). “Genetic and mutational    analysis of the T-cell antigen receptor.” Annu Rev Immunol 8:    139-67.-   Betts, M. R., J. M. Brenchley, et al. (2003). “Sensitive and viable    identification of antigen-specific CD8+ T cells by a flow cytometric    assay for degranulation.” J Immunol Methods 281(1-2): 65-78.-   Boch, J., H. Scholze, et al. (2009). “Breaking the code of DNA    binding specificity of TAL-type III effectors.” Science 326(5959):    1509-12.-   Boni, A., P. Muranski, et al. (2008). “Adoptive transfer of    allogeneic tumor-specific T cells mediates effective regression of    large tumors across major histocompatibility barriers.” Blood    112(12): 4746-54.-   Cambier, J. C. (1995). “Antigen and Fc receptor signaling. The    awesome power of the immunoreceptor tyrosine-based activation motif    (ITAM).” J Immunol 155(7): 3281-5.-   Carrasco, Y. R., A. R. Ramiro, et al. (2001). “An endoplasmic    reticulum retention function for the cytoplasmic tail of the human    pre-T cell receptor (TCR) alpha chain: potential role in the    regulation of cell surface pre-TCR expression levels.” J Exp Med    193(9): 1045-58.-   Cermak, T., E. L. Doyle, et al. (2011). “Efficient design and    assembly of custom TALEN and other TAL effector-based constructs for    DNA targeting.” Nucleic Acids Res 39(12): e82.-   Chames, P., J. C. Epinat, et al. (2005). “In vivo selection of    engineered homing endonucleases using double-strand break induced    homologous recombination.” Nucleic Acids Res 33(20): e178.-   Choulika, A., A. Perrin, et al. (1995). “Induction of homologous    recombination in mammalian chromosomes by using the I-SceI system of    Saccharomyces cerevisiae.” Mol Cell Biol 15(4): 1968-73.-   Christian, M., T. Cermak, et al. (2010). “Targeting DNA    double-strand breaks with TAL effector nucleases.” Genetics 186(2):    757-61.-   Coutinho, A. E. and K. E. Chapman (2011). “The anti-inflammatory and    immunosuppressive effects of glucocorticoids, recent developments    and mechanistic insights.” Mol Cell Endocrinol 335(1): 2-13.-   Critchlow, S. E. and S. P. Jackson (1998). “DNA end-joining: from    yeast to man.” Trends Biochem Sci 23(10): 394-8.-   Deng, D., C. Yan, et al. (2012). “Structural basis for    sequence-specific recognition of DNA by TAL effectors.” Science    335(6069): 720-3.-   Eisenschmidt, K., T. Lanio, et al. (2005). “Developing a programmed    restriction endonuclease for highly specific DNA cleavage.” Nucleic    Acids Res 33(22): 7039-47.-   Epinat, J. C., S. Arnould, et al. (2003). “A novel engineered    meganuclease induces homologous recombination in yeast and mammalian    cells.” Nucleic Acids Res 31(11): 2952-62.-   Geissler, R., H. Scholze, et al. (2011). “Transcriptional activators    of human genes with programmable DNA-specificity.” PLoS One 6(5):    e19509.-   Howard, F. D., H. R. Rodewald, et al. (1990). “CD3 zeta subunit can    substitute for the gamma subunit of Fc epsilon receptor type I in    assembly and functional expression of the high-affinity IgE    receptor: evidence for interreceptor complementation.” Proc Natl    Acad Sci USA 87(18): 7015-9.-   Huang, P., A. Xiao, et al. (2011). “Heritable gene targeting in    zebrafish using customized TALENs.” Nat Biotechnol 29(8): 699-700.-   Jena, B., G. Dotti, et al. (2010). “Redirecting T-cell specificity    by introducing a tumor-specific chimeric antigen receptor.” Blood    116(7): 1035-44.-   Kalish, J. M. and P. M. Glazer (2005). “Targeted genome modification    via triple helix formation.” Ann N Y Acad Sci 1058: 151-61.-   Li, L., M. J. Piatek, et al. (2012). “Rapid and highly efficient    construction of TALE-based transcriptional regulators and nucleases    for genome modification.” Plant Mol Biol 78(4-5): 407-16.-   Li, T., S. Huang, et al. (2011). “TAL nucleases (TALNs): hybrid    proteins composed of TAL effectors and FokI DNA-cleavage domain.”    Nucleic Acids Res 39(1): 359-72.-   Li, T., S. Huang, et al. (2011). “Modularly assembled designer TAL    effector nucleases for targeted gene knockout and gene replacement    in eukaryotes.” Nucleic Acids Res 39(14): 6315-25.-   Ma, J. L., E. M. Kim, et al. (2003). “Yeast Mre11 and Rad1 proteins    define a Ku-independent mechanism to repair double-strand breaks    lacking overlapping end sequences.” Mol Cell Biol 23(23): 8820-8.-   Mahfouz, M. M., L. Li, et al. (2012). “Targeted transcriptional    repression using a chimeric TALE-SRDX repressor protein.” Plant Mol    Biol 78(3): 311-21.-   Mahfouz, M. M., L. Li, et al. (2011). “De novo-engineered    transcription activator-like effector (TALE) hybrid nuclease with    novel DNA binding specificity creates double-strand breaks.” Proc    Natl Acad Sci USA 108(6): 2623-8.-   Mak, A. N., P. Bradley, et al. (2012). “The crystal structure of TAL    effector PthXo1 bound to its DNA target.” Science 335(6069): 716-9.-   Metzger, H., G. Alcaraz, et al. (1986). “The receptor with high    affinity for immunoglobulin E.” Annu Rev Immunol 4: 419-70.-   Miller, J. C., S. Tan, et al. (2011). “A TALE nuclease architecture    for efficient genome editing.” Nat Biotechnol 29(2): 143-8.-   Morbitzer, R., P. Romer, et al. (2011). “Regulation of selected    genome loci using de novo-engineered transcription activator-like    effector (TALE)-type transcription factors.” Proc Natl Acad Sci USA    107(50): 21617-22.-   Moscou, M. J. and A. J. Bogdanove (2009). “A simple cipher governs    DNA recognition by TAL effectors.” Science 326(5959): 1501.-   Mussolino, C., R. Morbitzer, et al. (2011). “A novel TALE nuclease    scaffold enables high genome editing activity in combination with    low toxicity.” Nucleic Acids Res 39(21): 9283-93.-   Pang, S. S., R. Berry, et al. (2010). “The structural basis for    autonomous dimerization of the pre-T-cell antigen receptor.” Nature    467(7317): 844-8.-   Paques, F. and P. Duchateau (2007). “Meganucleases and DNA    double-strand break-induced recombination: perspectives for gene    therapy.” Curr Gene Ther 7(1): 49-66.-   Pardoll, D. M. (2012). “Immunology beats cancer: a blueprint for    successful translation.” Nat Immunol 13(12): 1129-32.-   Park, T. S., S. A. Rosenberg, et al. (2011). “Treating cancer with    genetically engineered T cells.” Trends Biotechnol 29(11): 550-7.-   Pingoud, A. and G. H. Silva (2007). “Precision genome surgery.” Nat    Biotechnol 25(7): 743-4.-   Porteus, M. H. and D. Carroll (2005). “Gene targeting using zinc    finger nucleases.” Nat Biotechnol 23(8): 967-73.-   Rouet, P., F. Smih, et al. (1994). “Introduction of double-strand    breaks into the genome of mouse cells by expression of a    rare-cutting endonuclease.” Mol Cell Biol 14(12): 8096-106.-   Saint-Ruf, C., O. Lechner, et al. (1998). “Genomic structure of the    human pre-T cell receptor alpha chain and expression of two mRNA    isoforms.” Eur J Immunol 28(11): 3824-31.-   Sander, J. D., L. Cade, et al. (2011). “Targeted gene disruption in    somatic zebrafish cells using engineered TALENs.” Nat Biotechnol    29(8): 697-8.-   Smith, J., S. Grizot, et al. (2006). “A combinatorial approach to    create artificial homing endonucleases cleaving chosen sequences.”    Nucleic Acids Res 34(22): e149.-   Stoddard, B. L. (2005). “Homing endonuclease structure and    function.” Q Rev Biophys 38(1): 49-95.-   Tesson, L., C. Usal, et al. (2011). “Knockout rats generated by    embryo microinjection of TALENs.” Nat Biotechnol 29(8): 695-6.-   von Boehmer, H. (2005). “Unique features of the pre-T-cell receptor    alpha-chain: not just a surrogate.” Nat Rev Immunol 5(7): 571-7.-   Waldmann, H. and G. Hale (2005). “CAMPATH: from concept to clinic”    Philos Trans R Soc Lond B Biol Sci 360(1461): 1707-11.-   Weber, E., R. Gruetzner, et al. (2011). “Assembly of designer TAL    effectors by Golden Gate cloning.” PLoS One 6(5): e19722.-   Yamasaki, S., E. Ishikawa, et al. (2006). “Mechanistic basis of    pre-T cell receptor-mediated autonomous signaling critical for    thymocyte development.” Nat Immunol 7(1): 67-75.-   Zhang, F., L. Cong, et al. (2011). “Efficient construction of    sequence-specific TAL effectors for modulating mammalian    transcription.” Nat Biotechnol 29(2): 149-53.

1-40. (canceled)
 41. A method of expanding TCR alpha deficient T-cellscomprising: (a) Introducing into said T-cell at least a pTalpha or afunctional variant thereof to support CD3 surface expression; (b)Expanding said cells.
 42. The method of claim 41, wherein said cells areexpanded through stimulation of the CD3 complex.
 43. A method ofpreparing T cells for immunotherapy comprising: (a) Transforming saidcells with nucleic acid encoding a pTalpha or a functional variantthereof to support CD3 surface expression (b) Expressing said pTalpha orfunctional variant thereof into said cells (c) Expanding said cells,optionally through stimulation of the CD3 complex.
 44. The methodaccording to claim 41, wherein said pTalpha is truncated fromC-terminus.
 45. The method according to claim 41, wherein said pTalphais fused to a signal-transducing domain.
 46. The method according toclaim 5, wherein said signal-transducing domain is selected from thegroup consisting of: CD28, OX40, ICOS, CD137 and CD8.
 47. The methodaccording to claim 41, wherein said pTalpha comprises protein sequenceselected from the group consisting of SEQ ID NO: 107 to SEQ ID NO: 124.48. The method according to claim 41, wherein said pTalpha is fused toan extracellular ligand-binding domain.
 49. The method according toclaim 8, wherein said extracellular ligand-binding domain is a singlechain antibody fragment (scFV).
 50. The method according to claim 41,wherein said pTalpha or functional variant thereof is introduced intothe cell by the way of RNA electroporation.
 51. The method according toclaim 41, wherein deficient TCR alpha T cells are obtained by a step ofinactivating TCRalpha gene.
 52. The method according to claim 11,wherein said TCRalpha gene is inactivated by introducing a rare-cuttingendonuclease capable of inducing a DNA cleavage within TCRalpha gene.53. The method according to claim 12, wherein rare-cutting endonucleaseis TALE-nuclease.
 54. The method according to claim 13, whereinTALE-nuclease is targeted against one of the gene target sequence ofTCRalpha selected from the group consisting of SEQ ID NO: 37 and SEQ IDNO: 57 to
 60. 55. The method according to claim 41, wherein said T-cellsare further exposed with bispecific antibodies comprising a firstbinding domain which binds a therapeutic target and a second bindingdomain which binds a T cell antigen.
 56. The method according to claim41, wherein a Chimeric Antigen Receptor is further introduced into saidT-cell.
 57. The method according to claim 41, further comprising a stepof inactivating a gene encoding a target for an immunosuppressive agent.58. The method according to claim 41, comprising introducing into saidT-cell a TALE-nuclease able to selectively inactivate by DNA cleavagePDCD1 or CTLA-4 gene.
 59. The method according to claim 41, wherein saidT-cell is recovered from a patient diagnosed with cancer or infection.60. A pTalpha polypeptide comprising at least a fragment of pTalpha orfunctional variant thereof fused to an extracellular ligand-bindingdomain.
 61. The pTalpha polypeptide of claim 20, wherein saidextracellular ligand-binding domain is a single chain antibody fragment(scFv).
 62. A pTalpha polypeptide comprising at least a fragment ofpTalpha or functional variant thereof fused to a signal transducingdomain.
 63. The pTalpha polypeptide of claim 22, wherein the signaltransducing domain is selected from the group consisting of CD28, OX40,ICOS, CD137 and CD8.
 64. A pTalpha polypeptide comprising sequenceselected from the group consisting of SEQ ID NO: 107 to SEQ ID NO: 124.65. A polynucleotide encoding a pTalpha polypeptide according to claim60.
 66. An isolated TCRalpha deficient T cell comprising an exogenouspTalpha polypeptide.
 67. An isolated T-cell or cell line obtainable fromthe method of claim
 41. 68. An isolated T-cell comprising a pTalphapolypeptide according to claim
 60. 69. A pharmaceutical compositioncomprising at least one isolated T-cell according to claim 66.